Ever wonder how to score upgrades and bonus miles during your flight? Is there an ideal time of the day, or of the year, to fly? And just how clean are airplanes? We found out answers to all of these burning questions … and more. In the latest in our ongoing series, How to Get Better Service, NBC News BETTER sat down with Stella Connolly, a veteran New York-based flight attendant, and the personality behind the YouTube channel, Fly With Stella. Connolly has spent years working for one of the nation’s biggest airlines and told us the dirty little secrets of how to score better service and more frequent flyer miles when you fly.

The best times to fly (and days to avoid)

Wondering when is the best time of the day to fly? Warning to night owls: You’re not going to like Connolly’s answer.

“Early morning flights are the best,” said Connolly. “They’re almost always on time. As the day goes by, if one flight is late it’s a snowball effect and there’s a higher chance flights will be delayed. I recommend flying early.”

An on-time flight means not only will you get to your destination quickly, but also that you’ll be working with a flight crew that’s typically in a better mood.

Connolly said that people often forget that just as passengers don’t like delayed flights, neither do flight attendants. “We want to get home or get to our destinations just as much as you do,” said Connolly. “We’re happier if the flight takes off on time.”

Connolly said early flights will also enable you to enjoy a cleaner aircraft. Planes are generally cleaner first thing in the morning, after crews have had a chance to do a thorough cleansing of the cabin.

As for times of the year that are particularly difficult to fly?

“The worst time to fly is the holidays,” said Connolly. “On any holiday weekend, everything is completely booked.”

When flights are overbooked, Connolly said there are few, if any, opportunities for upgrades or seat changes. There are also additional challenges: little if any room in the overhead luggage bins (which means you might be asked to check that bag you’d hoped to carry on) and crowds that can contribute to a tense mood on the entire aircraft.

Some passengers try to game the system and fly on Christmas Day or on Thanksgiving Day, thinking fewer people will fly on the actual holiday than during the days leading up to it, but Connolly warned those days are stressful, too, and aren’t as quiet as you might hope.

“Even on the actual holidays it’s really hard to fly. For the best flights, try to avoid holiday travel.”

Being a frequent flyer on an airline gets you noticed

Want to know a surefire way to score more attention from a flight crew? Fly frequently on that airline and “up” your status.

Connolly said flight attendants can see the flight status of everyone on a given flight. Customers who fly the most frequently on an airline get noticed and can score additional in-flight perks.

These perks can range, Connolly said, from scoring seat upgrades, to being given other kinds of preferential treatment.

Connolly said that flight attendants know who you are, and what “status” you hold on an airline, from the moment you step foot on the plane.

“We have the list of passengers who are frequent flyers,” Connolly explained. “If they have status on our airline, their names are highlighted in a different color on our tablets. We know where they’re sitting. It definitely makes a difference. We definitely appreciate them for their loyalty in staying with our company.”

Connolly said that the perks extended to frequent flyers include free drinks and sometimes better food options.

“We always want to thank our executive platinum, our gold platinum flyers,” Connolly said.

When something goes wrong, speak up (it could mean immediate bonus miles)

Connolly said she’s well aware that sometimes on flights, mistakes happen.

And when they do, she said passengers shouldn’t be afraid to politely speak up.

Connolly said flight attendants are increasingly able to make up for inconveniences by rewarding passengers bonus frequent flyer miles, instantly, using their hand-held devices.

“It’s a new thing,” Connolly explained. “Now on the tablets that we flight attendants carry, we’ve been given the power to immediately give customers bonus frequent flyer miles by pushing a button in our pulldown menu labeled ‘Customer Inconvenience'.”

Flight attendants can give passengers bonus miles in an attempt to make up for broken seats, glitchy entertainment systems, or not having a special meal on board that the customer ordered in advance.

“Now if something happens, like a drink is accidentally spilled on a customer, we can make it up to the customer right away and they know they’ll have additional frequent flyer miles in their account when they land,” Connolly explained.

It’s all part of the airlines’ growing awareness, she said, that customer service is key and that passengers don’t want to have to go through layers of customer service agents after a flight, in order to voice concerns.

The airline has a few “extras” … all you have to do is ask

Among the extras: closet space. Connolly said a lot of passengers are not aware that many planes have closets. So if you’re bringing a suit or special outfit to change into upon landing that you don’t want wrinkled, or if you’re traveling with a wedding gown that you don’t want to pack into a suitcase, don’t be afraid to ask the flight attendant to lead you to the nearest closet.

“If a passenger wants to hang something up most of the airplanes have extra closets,” Connolly explained. “Definitely ask.”

Connolly also noted airplanes often have one bathroom that’s bigger than the others.

“On bigger planes, there’s one bathroom designated as a bigger bathroom and if you want to change your baby or if you want to change into pajamas or a suit for when you land, you can always ask the flight attendant to direct you to the biggest bathroom.”

Flight attendants can also supply passengers with items they may find a need for at the last minute, including aspirin and feminine products.

And while planes don’t officially supply planes with chewing gum, Connolly said she doesn’t know of flight attendants who don’t carry gum, so if you’re in need of gum to help you pop your ears when the plane is descending, she says you can always feel free to ask.

Connolly noted there are also perks available to children that are not advertised, but provided to parents who ask.

“Most planes carry wings for the kids that can be pinned to their clothes,” Connolly said. “Some airlines give out little kid passports, where the kids get a stamp each time they fly. And pilots also are happy to show kids the cockpits before a flight. So when you board the plane, it’s a good time to ask for a tour or a photo.”

Finally, Connolly said, if you’re on a plane that’s running late, and you’re worried about to making a connection, don’t be afraid to let the flight attendant know.

“If you make us aware of the situation, we can make an announcement before passengers deplane, asking them to let passengers with connecting flights deplane first,” Connolly explained. “We try to work with passengers that are in a hurry, and in need of making their connections.”

Just how clean are airplanes? You might not want to know

“If you’re a germophobe, bring your own sanitizer whenever you fly,” Connolly advised.

Connolly said the turn-around time between flights is extremely quick, especially if a plane lands late and passengers for the next flight are anxious to board. That means there’s minimal time for a clean-up crew to sanitize things for the next flight.

“Cleaning crews don’t have time to do much between flights,” Connolly explained. “Trash is picked up after the plane lands, bathrooms are cleaned and the aircraft is vacuumed.”

There’s no time, Connolly said, for deep cleaning.

Connolly said for this reason, passengers should be especially careful of tray tables, which are not wiped down between flights.

“The person sitting there before you could have been drooling all over the tray table while they slept,” Connolly said. “Diapers are changed on tray tables, people even put their feet on tray tables.”

As for pillows and blankets? Connolly noted you might want to bring your own pillow or at least your own pillow case. “We try to change out the pillow cases,” explained Connolly, but noted there are no guarantees.

She advises that people who want to feel better about the cleanliness of their flight to bring their own antibacterial wipes to wipe down tray tables and arm rests and to come armed with their own pillows and neck rests.

Pay attention to new trends in on-board entertainment

You know how in-flight entertainment has evolved in recent years from big movie screens for the masses to individual flat-screen monitors? Well, in-flight entertainment is evolving again.

“The problem with those monitors is that they don’t consistently work,” Connolly explained. “Our airline is getting rid of the screens. There are so many problems with the screen. Sometimes they don’t work and if it’s a five hour flight — and the customer has nothing to do. It’s frustrating for the customer and it’s frustrating for flight attendants.”

A growing number of commercial airlines, like Connolly’s, are moving in the direction of in-flight entertainment apps that can be downloaded to individual phones and tablets. Connolly encourages passengers who want to have in-flight entertainment to find out from gate agents prior to boarding, if in-flight entertainment systems are available, and if so, to download those programs and apps to devices, prior to departure, and make certain that they work before take-off.

Bonus round: What about those throwback ashtrays and the 'Mile High Club'?

We had to ask Connolly to tell us the strangest thing she’s ever seen on a flight … and to answer some final burning questions.

First, the strangest thing she’s ever seen on a flight?

“That would be the time a passenger brought a full-size microwave on the plane as her carry-on item,” Connolly said. “It was really interesting. It fit the size requirements. It fit in the overhead bin, so the microwave came with us.”

We also wanted to know how come brand new aircraft still have ashtrays on them, even though smoking on flights is prohibited.

“Commercial aircraft are required to have ashtrays,” Connolly explained. “We still have to have those ashtrays just in case anyone is smoking so that we have an area to safely extinguish the cigarette.”

Finally, we had to ask: Is the Mile High Club a myth or a reality?

“Have you seen how small the airplane bathrooms are?” Connolly responded, laughing.

Connolly said she hasn’t caught any passengers trying to have sex in an airplane bathroom, but she is aware of couples trying to get intimate in their seats, during a flight.

“One of my colleagues caught a couple doing things in business class,” she said. “We had to let them know they couldn’t share a seat that way.”

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