connection time at lhr
 

I am arriving BMI Terminal1 from Edinburgh supposed to arrive 12:15. Have to collect luggage, get to terminal 3 and on AA flight to Dallas that leaves at 3:15. Is this possible?

Easily, but BMI and AA have interline baggage agreements, so you ought to be able to check bags all the way to DFW at EDI. Just make sure the BMI person sees/knows your AA flight details. Even if not, it shouldn't take terribly long to get to T3 with bags. Two tickets?

I wasn't sure they would check me through at EDI since it is a seperate trip and ticket. That would be great if they will, wont have to wait for baggage. Thanks for the info!

If it's two tickets they might refuse, but they have the ability to through-check the bags, so no harm in asking. You'll need full details (flight number, reservation record locator etc.) on the AA flight when you check in.

I've done this before with seperate tickets and they have never refused to check my bags all the way through.