12a variety of military aircraft? (4-6) ?I?E ?E???R
15a for that very reason (4-5) ??S? F????
21a window material (5-5) ????? GLASS
48a crisp salad vegetabale (6) ??????
7d hoard up (9) ?T?????L?
8d goat known for its silky wool (6) ?N????
9d enmesh (6) ?A?G??
31d master or mistress (13) ?C?O?L?L?C?E? Think it may be schoolteacher so the 2nd L may be wrong!
40d stale joke or story? (3-8) OLD ??R?T?U?
44d research deeply? (5) D???E
49d secure way to tie strimg (4-4) ??E? LOOP