i think the idea of flying tank is not economically accepted especially comparing it's benefits which are really small.
but the idea of using laser at an areal vehicle is interesting. if you by any chance visited Turkish laser section in the forum, you can see a man portable laser attached at their mpt-76 battle rifle with penetration range of 150 m, 30 minutes duration of unceasingly illumination and penetration rate of 2-3 cm.
yeah i know you might think it's a crappy specifications for a attachment of a rifle but what if we arm our quad copter drones with them?? it suddenly makes sense.
it can penetrate inside of a tank Armour and case the rounds stored in back of tank to explode. do the same to munition stockpiles, cause enemy vehicles to burn, etc.
and more interesting than all of these is plasma rail gun, in this particular weapon your projectile is plasma, your rate of fire is between 100-1000 RPM. however it's weight will be heavy and it will need a power source makes it suitable for vehicles like tanks or APCs.