One thing you can do, if your opponent is a fan of deep strike, is to keep things in reserve. Then, his stuff comes in shoots a couple of your units, then your reserves can pounce on him. Alternatively, get cheap units (like cultists), to bubble wrap your army.
If you bubble wrap, he has do deploy outside of your screening line. he wont be able to melta your tanks, and will be in a good spot to be pounced on by your other units.
Terminators are slow, so can either be avoided, or dealt with by weight of fire. A bunch of Ap2 attacks can also help, but you need to put a really weight of fire on them so they fail their saves.
I'm not sure which flyer you're talking about, as the Dark Angels have no access to flyers with transport capacity.
What are your running? What is his list like?