trillions of dollars over budget and almost a decade behind schedule . These are both massive exaggerations . The F 35 isn ' t even replacing the A 10 , the F 35 replaces the F 16 . The A 10 was replaced for front line combat roles in the 90 s by the F 16 , during desert storm , where it ' s losses were too high when it faced enemies that could fight back with even somewhat modern SAMs . Heck , even during the 70 s 80 s , USAF was doubtful about how well it would perform against the red army , with many casualty predictions stating that the A 10 force would last only days in a cold war gone hot scenario in Europe . Since then the A 10 has been limited to COIN counter insurgency fighting against enemies that don ' t have SAMs or radar guided AAA . The A 10 is very inefficient for this role and the airframes are getting old and expensive to maintain spares are largely cannibalised at this point . The gun and armor weigh over 3 tons and do basically nothing they were intended for fighting against large numbers of 1950 s era soviet tanks that would be protected largely by dumb AA 12 . 723 mm , the gun cannot deal with 1970 s tanks whilst being massive overkill for COIN an equivalent 20 mm armament weighs a third as much and the A 10 is still vulnerable to radar AAA and manpads regardless of it ' s armour because it ' s slow and low . For COIN it ' s much more cost effective to use drones or light attack aircraft ie tucano , m 346 . For a war where the enemy has modern AA the A 10 is just flat out useless .