Next month I'm flying LHR-SEA-KOA. The first leg is with BA and the second Alaska.

Eta 16.15. Etd. 18.20

Is this doable? I'm concerned that it's a very tight schedule as I'll have to clear immigration, collect my bag and clear customs then recheck bag, do through security and board. I'm also flying economy so will be one of the last to leave the plane.

I've done this route in reverse but then had about a 6 hour transit time.

Previously, I've flown LHR-LAX-KOA but had a 5 hour transit time. I remember it took a couple of hours to pass through the queues and checks.

Thanks for any advice.