When US Airways was hiring they hired about 1/3 commuter, 1/3 corporate/freight/135, and 1/3 military.

Most of the big name carriers generally are now hiring commuter check airman and military IP's. On the first page of AA's app it asks if you have been an astronaut or fighter pilot as check boxes...

Yes it's possible but another big thing with moving on is networking and knowing people. You won't find many in that world moving on, limiting your connections.