In four years, I have had two jumpseaters and one pilot who was non-revving offer to write me a letter of recommendation. The non-rev was an interesting situation because he was trying to make a tight connection and he asked me if I could look after a fragile gate checked bag, which I did and I brought it up to him. I never asked a jumpseater for a letter of recommendation, but when they offered I took the necessary steps to receive it. This means you need to have your apps already filled out and ready to be published. Internal recommendations are now mostly done electronically so you need to have your pilotcredentials and airlineapps accounts already made and you need to follow up with the pilot who is making the recommendation.

I had been networking quite a bit and had internal recommendations at my target airlines, but it was the last jumpseater who wrote the LOR that got me an interview for my current job. So you never know.