You wont be eligible for an M1 visa since going for recency is not training
Make sure you have a letter from the flying school to present to the U.S consulate stating that you need to do recency for meeting Indian DGCA requirements
Keep the letter in hand when you enter the U.S as you might have to present it to the immigration officer .
They wouldnt let one of my friend through at the customs until he showed them this letter despite have a valid visa