With air travel, its the consumption that normally causes the negative externalities such as air pollution right? So a minimum price scheme would actually deter consumers from using air travel as its obviously more expensive. So you could say that the minimum price actually internalises the external cost. However, minimum prices usually result in excess supply so you could argue as an opposing point that the resources used to produce this extra supply could have been used more efficiently elsewhere, hence creating government failure as resources are being misallocated. You could also say that the governments imposing this minimum price might have to purchase the excess supply or fund it, hence administration costs arise resulting in further market and government failure. Therefore other schemes such as indirect taxes, trade pollution permits could be a more viable option.
Another point that could be made is that if governments impliment indirect taxes on aviation, in the short run consumption won't decrease due to being inelastic, however in the long run the government could use their excessive revenues for the provision of information such as the disadvantages of air travel in the hope that it will make consumers more elastic.
These are just points from the top of my head but there are obviously many more.
My AS Economics exam is tomorrow? Is yours? Anyway, Good luck!