Experienced simulator instructors. This is how F-22, F-35, and other single-seat pilots learn before flying the actual jet solo for the first time. "Level D" S

Experienced simulator instructors. This is how F-22, F-35, and other single-seat pilots learn before flying the actual jet solo for the first time. "Level D" Simulators for transport aircraft are extremely realistic. In the air, airliners have near constant communications with dispatch and would be able to phone home for any emergencies that require an additional or higher-level decision maker. This discussion is a lot more complicated, and I don't think we'll see single-seat airliners for many decades anyways. Just wanted to answer your question.