Can't answer for the other Services, but the Army Flight Physical CAN be accepted by the AF. Operative word is CAN. It depends on several circimstances---most prevalent is that the Army physical checks the items the AF requires and does it by the AF approved method. If the Army physical covers all the items, and it is recent (I don't know the time limit, but it is short) the AF CAN accept it . The biggest problem will be if a new AF Flight Surgeon has never seen this before.

But, I've done it many times.

Here is an excerpt of the Air Force Regulation that allows one to use another Service's flight physicals.

NOTE: "MAJCOM/SG" that receives your physical means "Major Command Surgeon General". In your case, if you are entering the AF to fly, it will be the AETC/SG or the "Air Education and Training Command's Surgeon General"....They are located at Randolph AFB TX. Your Army facility would forward your results to them.

AIR FORCE INSTRUCTION 48-123
24 SEPTEMBER 2009

Aerospace Medicine MEDICAL EXAMINATIONS AND STANDARDS

1.2.2. Examiners: A credentialed military flight surgeon with privileges in flight medicine will perform medical examinations on Air Force flying and/or special operational duty personnel. When seen by a non-Air Force flight surgeon, forward the documents (physical assessment, etc.) to the examinee’s MAJCOM/SG for review and certification. All aircrew members examined by a U.S. military flight surgeon and found qualified to perform flight duties will be returned to flying status upon completion of their examination.
1.2.2.1. Military flight surgeons must be credentialed and privileged at the examining facility and can be of any branch of the military service