There are no schemes as such, but in times when jobs are relatively easy to come by and pilots not so, some airlines have in the past reserved places for ex-military pilots. Whether they would do the same for you is moot, but the only way you will find out is to contact them. It will only be an individual (and informal) arrangement between you and an airline, and nothing will be guaranteed, but it may be worth a shot. However, never forget that you are in competition with thousands of wannabes who will kill to get a shot at any job, so don't be surprised if you get nowhere!
Scroggs