The strangest part about getting on an airplane is how eager we are to do it. Crowded at the back of the gate, awash in a mix of communal panic and stress, we look at the ticket again and again. What group are they calling? What group am I? I bet half these people are cheating, and the gate agent is letting them get away with it!

We're not talking about access to a buffet here. We're stepping into an uncomfortable, stuffy tube in which we'd count ourselves lucky to sit alongside someone who won't talk our ear off or fall asleep on our shoulder. At best, that stress-panic will morph into resignation or quiet frustration once we're packed in.

So why the rush? Ah, yes. The bag. The bag you refuse to check because it means forking over another 25 bucks and waiting at the carousel and risking seeing it lost or mangled by some gorilla of a baggage handler. The sooner you're crammed into that metal tube, the better your chance of cramming your wheeled armoire into that tiny space the airline industry allots over your head.

That could change with the new "space bins" that Boeing's adding to the 737. They'll hold 50 percent more bags than the current design, which means you won't have to worry about that idiot in 17D crushing your bag with the over-stuffed rollerboard he really should have checked. The key, says Boeing engineer Derek Minyard, was making the bin big enough to insert a bag in on its side rather than its back.

Boeing also moved the lower edge of the bin down 2 inches, making it easier to reach. It tweaked the balance, making the whole thing easier to to shut, so the "close assist" mechanism—which adds weight, which airlines hate—is now unnecessary.

Travelers who have tried the new system seem impressed. "Boarding will be a lot quicker. Plus, I won't have to help my girlfriend load her bags because she can reach these bins a lot easier," says Daniel Jones, a frequent flier and not exactly Sir Galahad.

Changing the size of the compartment is easy: Make it bigger. The tricky part is doing that without encroaching on the already limited space for, you know, humans. That meant going through many iterations of the bin's profile, Minyard says. The space bins will cut head room by 2 inches, but Boeing swears that's a good thing: The overhead light and air vent will be easier to reach.

The bins, showcased this week at the Aircraft Interiors Expo in Hamburg, will be installed on the 737 MAX, coming in 2017. They can be retrofitted into any of the more than 5,000 737 Next-Generation jets now plying the skies, and Boeing strove to avoid introducing new parts and mechanisms to keep costs down. Still, just what it will cost to add the bins hasn't been determined yet.

Alaska Airlines is the launch customer and should take delivery of a 737 with the spacious bins by year's end.