The latest M1 visa that I have received was in June of this year.
Phoned the US Embassy on their premium rate telephone line and was given the earliest possible date of four weeks later.
Then it was a whole day out at the US Embassy (again!) for a three hour wait at the Embassy for the 1 minute interview (if that) and finger prints taken.
The visa arrived stuck in my passport two days later. They say to allow up to 10 working days for arrival and someone has to be at home to sign for the package. Don't forget the £10 (cash) that they require at the Embassy to send your passport back to you...
Lastly very glad to hear the flight school you will be attending won't touch you without a visa. Sounds like they are doing things correctly.