I paid for my daughter to do the iFly experience because the free options were all taken, even before we boarded the ship, and if any additional free slots opened up after boarding, we were never able to find them.
We also questioned how the 2 minute limit was gonna be, but my daughter said after doing it, she understands why it's so short, and she felt like it was plenty of time.
They actually put about 5 people in a group and the session itself lasts around half an hour (maybe even a whole hour if you include the safety briefing and getting fitted for the outfit, helmet and goggles).
Then once they get to the iFly portion, each person goes in for a practice for maybe 30 seconds, then they watch the other people do their practice, then go back in for another 30 seconds, repeat, then I think the 3rd time they go in for a full minute.
My daughter said that with all the wind blowing at you, it takes a lot of work to keep your form correct, and being in there for longer wouldn't have started to diminish the enjoyment.