what does beaty mean by "now you did it. old montag wanted to fly near the sun and now that he's burnt his damn wings, he wonders wh. didnt i hint enought when i sent the hound to your place

In Section 3 of Fahrenheit 451,the mythic allusion on is a comparison of Montag to Icarus,

Old Montag wanted to fly near the sun and now that he's burnt his damn wings, he wonders why.

The story of Icarus involves Icarus and his father Daedalus trying to escape from Crete. They uses feathers with wax holding them together. Daedalus warns his son not to fly too low or too high as the sun will melt the wax or the damp sea will weaken the wax. Icurus flies way too close to the sun and he crashes down into the sea.