[hopespringseternal]

Why don't we use laser's for missile defense on ships and cities? I would think applying the technology to those areas would be a lot easier than trying to mount it on an airplane.

Because mounting it on an airplane solves the problem of running out of ammunition. While the movies show aircraft blasting away with chainguns for minutes at a time, the truth is that ammunition tends to be heavy and aircraft go through it very quickly. Most aircraft, especially fighters, only have a few seconds of ammo.

Also, consider that you don't have to lead the target anymore and he can't evade your fire.

[Myrddin]

Because mounting it on an airplane solves the problem of running out of ammunition. While the movies show aircraft blasting away with chainguns for minutes at a time, the truth is that ammunition tends to be heavy and aircraft go through it very quickly. Most aircraft, especially fighters, only have a few seconds of ammo.

Thus the phrase, "the whole 9 yards" referring to the length of a full magazine of belt fed ammo on the aircraft.