You’re a private pilot, out on a Sunday jaunt in your single engine prop plane. Lovely day for a flight—calm skies, good weather. Then you hear, feel, and then see the fast approach of two, grey, angular military jets, flying terrifyingly close to you, most definitely armed and dangerous.

What have you done? More pressing, what do you do? Chances are, you’ve strayed into restricted airspace, like the no fly zones put in place to protect President Trump wherever he goes, or special events, like this weekend's Super Bowl.

For the big game, the no-fly zone banishes planes (and drones, the FAA is keen to stress) straying within 34.5 miles of NRG stadium, in downtown Houston. If pilots feel they must enter the outer edge of the perimeter, they need permission from controllers, and are asked to maintain constant contact. The 10-mile core is strictly no entry.

OK, back to those menacing fighter jets, one of which is now level with you, where you can see each other. Hopefully, as a pilot, you’ve read and memorized your in-flight intercept procedures (even if you didn't bother to check the FAA website for no-fly zones in your area), because they're your best bet for keeping a lot of airspace between you and a missile.

Step one, rock your wings to acknowledge the intercept, the way a driver hits his turn signal when he sees a cop pulling him over. The jet pilot will be trying to communicate, so answer your radio if you can, and explain how sorry you are. The lead jet will likely turn, guiding you out of the banned area—follow it. If it abruptly turns across your nose and fires its flares, it's meant as a warning—so follow it, like immediately.

If you can’t comply for whatever reason, switch all your lights on and off at regular intervals. If you’re in distress, maybe due to mechanical failure, do the same, but at irregular intervals (just something else to remember in an emergency).

Turns out that small planes stray into restricted airspace all the time. "Most of the time, before they even get near the restricted area, officials contact them on the radio," says Stephen Bucci, visiting fellow for Homeland Security and Special Operations at the Heritage Foundation. "They turn them right or left, and that’s the end of it.” But after September 11, 2001, enforcement got more serious. Pilots have intercepted more than 1,800 non-military aircraft since the attacks, according to the North American Aerospace Command (Norad).

So, while a studious pilot should go a lifetime without being bothered by an F-16, fighter jet jockeys spend a lot of time training for this specialized dance.

This week, the Civil Air Patrol, the civilian auxiliary of the Air Force, whose 56,000 members are mostly retired and civilian pilots, has been deliberately flying into mock restricted areas around Houston, running through exactly the scenario above, to help military crews practice for any possible encounters this weekend. Volunteers spent two days flying two Cessna 182 planes low and slow, for the Texas Air National Guard to intercept.

FAA

“What we’re training for is the pilot who wanders in some place, where they’re not supposed to be, and is going to cooperate," says the CAP's Colonel Brooks Cima. After all, that's the most likely scenario. Pilots are supposed to check daily notices for up-to-date air closure information, but mistakes happen, especially when those closures take effect with little notice, like when POTUS sweeps into town.

To keep everyone sharp, CAP flies 1,450 training missions a year, focussing on simulating everything from presidential inaugurations to meetings of world leaders. It's all part of Operation Noble Eagle, which the US and Canada jointly launched after 9/11. The military uses a few different aircraft, but F-15 and F-16 jets are popular choices, along with Black Hawk helicopters, since the rotary craft have an easier time flying slowly alongside small, slow planes.

For anyone who buzzes into closed off territory, the fighter jets and persistent radio calls are usually enough to intimidate them into behaving. If not, things step up a notch.

“If it becomes clear that the aircraft has hostile intent, they will get permission to engage it with weaponry,” says Bucci. He worked in the Pentagon after 9/11, when Norad was developing the new rules for how and when to take a plane out. Initially, responsibility for making that call rested with the Secretary of Defense, but is now routinely delegated down to the two-star officer on duty at Norad’s Colorado Springs base.

For special events like the Super Bowl or last month's Inauguration, the Secret Service runs the show, and its senior agent on the ground will be the one to authorize action. “It will only happen when everything else has been tried,” says Bucci, and everything else usually works. To date, a civilian plane has never been shot down in the US, not even the gyrocopter a publicity seeker landed on the lawn of the US Capitol in 2015—in some of the most restricted airspace in the country.

Although the risk is low, exercises to keep skill levels high have a secondary benefit: They are a ton of fun for the retired military and civilian pilots who make up CAP. For them, these drills provide the thrill of seeing military aircraft in action, up close and personal. For the rest of us, it’s just one more level of protection.