UAL/Lufthansa Career Path Program
https://www.lufthansa-flight-trainin...ammfuerpiloten
You pay for your CFI, get hired by ATCA (see above), get your 1500 hours/ATP, and then you're online at UAL mainline.
AA has a sort of similar program, except when you get your 1500 hours, you go to Envoy, then AA later.
Jet Blue has a Cadet Program, but it's very, very expensive.