Make the box bigger so that it could carry men and or vehicles............. Oh hang on we already did that, they were called Horsa and Hamilcar.
Almost 20 years ago I was stood on a South African DZ watching a Herc disgorge a full load of para and due to the DZ altitude / temperature and a bit of a tailwind the spread of troops on the ground was thin. First man out was over 5 Km from last man out. I thought then that the idea of the assault glider could make a comeback. Lots of troops in a small space at a fraction of the cost and noise of a Chinook.