###While we are not given any complete indication, it is a safe bet that Nick Fury did not send in attack aircraft because they were more of a threat to the civilian population than they would be an asset to the Avengers. Conventional military air support has a great deal of collateral damage involved, something Nick Fury is hoping to prevent.
While we are not given any complete indication, it is a safe bet that Nick Fury did not send in attack aircraft because they were more of a threat to the civilian population than they would be an asset to the Avengers. Conventional military air support has a great deal of collateral damage involved, something Nick Fury is hoping to prevent.
We see the chaos with Thor, Hulk and Iron Man fighting in the lead against the Chitauri with Captain America, Hawkeye and Black Widow fighting a ground battle. Air-to-air combat using fighter jets would have meant air-to-air missiles (whose effectiveness could only be guessed at) and .50 caliber rounds filling the air, penetrating buildings and causing mass casualties among civilians.
In theory, this is why the Avengers were called. As living weapons, SHIELD expects the Avengers to do their best to both limit casualties and direct their intelligence onto finding a way to stop the enemy without inflicting more casualties than the military would using conventional weaponry.