One reason for the decline is that the Air Force is asking pilots to commit to longer stints. Also, with airlines taking significant financial hits in recent years, some military pilots are deciding not to join a commercial carrier when they retire from the service, according to industry experts.
In addition, the pool of available pilots with military backgrounds is limited, which means airlines have had to turn more often to civilian ranks when they've hired more pilots.
The pilot who guided a crippled US Airways jetliner safely into the river in New York on Thursday, saving all 155 people on board, flew F-4 fighter jets with the Air Force in the 1970s. Chesley B. Sullenberger III was credited with staying calm when both engines failed after being struck by birds, and herding passengers of Flight 1549 to safety after splashing into the Hudson.
Brad Bartholomew, an airline pilot who has served in the military and has studied airline labor issues through his work at a Southlake, Texas, consulting firm, said he received training in the military he thinks is valuable to pilot ranks. Military pilots are trained in simulators of aircraft they might fly and also go through classroom training. The difference for commercial pilots is their training might be more condensed than in the military, though it would still be similar.
"A civilian pilot can make the same cool decision as a military pilot can." Bartholomew said.
Military training helps pilots deal with stressful, dangerous situations, according to pilots who've flown in the service. They point out, however, that the most important thing for commercial airline pilots is to have enough experience flying and have mastered the required flying standards, things they can learn over time as seasoned civilian pilots.
Tad Hutcheson, a spokesman for discount carrier AirTran Airways, said airlines don't institute tougher training for pilots who have not served in the military.
"It's the same training regardless of where you came from," Hutcheson said. "We have different levels of standards in terms of hiring. Some airlines require a certain number of hours. At AirTran, we require a minimum 2,500 hours flight time with at least 500 hours of pilot in command time. We're only hiring people who have been captains in a previous life, be it in the military or for other airlines."
Sullenberger, who has flown for US Airways since 1980, has served on a board that investigated aircraft accidents and has studied the psychology of keeping airline crews functioning in the face of crisis. He also had an experienced co-pilot at his side - Jeff Skiles, a US Airways veteran of more than 20 years. A law passed in 2007 increasing the mandatory retirement age for U.S. commercial airline pilots from 60 to 65 means airlines will be able to keep experience in the cockpit longer.
Neither military nor commercial training prepares a pilot for all eventualities when flying an airplane. Some emergencies aren't in the book, and the response is based on expertise, training and in some cases a lot of luck, pilots say.
Joe Mazzone, a retired Delta Air Lines captain, said even in the Air Force he wasn't specifically trained on how to do a water landing - like the one Sullenberger pulled off - safely beyond being shown diagrams and pictures of what a plane should do under ideal conditions when it hits water.
"That's a rare occurrence and it's hard to duplicate," he said.
Keith Rosenkranz, who flew 30 combat missions in the 1991 Persian Gulf War and has been a Delta pilot the last 17 years, said airline simulators he's been around don't have simulated birds or anything like that, but pilots are taught to maneuver out of the way of something dangerous if they can do so safely.
"If you see a large flock of birds out from the runway, you're not going to take off yet," Rosenkranz said. "If you see them as you attempt to land, you might do a go-around."