As a reminder, United splits training into five phases, they are as follows:
- Systems
- Procedures
- Maneuvers
- Line type experience in the simulator
- Operating experience in the actual jet.
The fifth and final stage of getting checked out in a new airplane is actually flying the jet with a special Captain known as a “Check Airman”. As a quick aside, the term “airman” applies to both men and women. These flights are actual revenue flights with passengers, that serve as training flights as well. There are of course no emergencies practiced (unless something actually happens), instead the flights are focused on normal operations in an airline environment.
I flew a two day trip and a four day trip, for about 28 hours of total flight time, with two different check airman. I had not flown since August due to a medical issue, so I was a bit rusty getting in the airplane. I would say it took me until the third day of flying to start feeling comfortable again. I was signed off on the last day and released to fly the line.
I just finished my first trip since my Operating Experience was completed, it is nice being back in the saddle and flying again. I will be honest, I had forgotten how much I enjoy flying.
It is worth noting that my first co-pilot was another ATP alumni 
737 NG cockpit
Inside the wheel well of a 737
Another wheel well picture