Just to clarify what Soulyss posted, the small buildings/structures in the terrain (like the little red barns) can't be destroyed/damaged. Structures on airfields, in ports, towns, etc can mostly be damaged/destroyed although not in all cases. Strafing is not super effective with smaller calibre guns though so the results can be mixed. A player in AH1 did a comparison of damage by calibre and converted to lb's equivalent and found something in the 12.7mm/.50cal class of weapon did about 1.1lb's of damage on average per hit. So, small ground targets like fuel bunkers which take ~250lb's to destroy would be destroyable without too much effort but hangers tend to take several passes and lots of hits. That said, in a pinch, of if you have larger calibre weapons, strafing can be quite effective.
