Quick question for any Heathrow denizens. Is it possible to go from one international flight (from NA) and immediately go to your flight back home without having to go through customs, etc... I use either UA or AC, which are both housed in Terminal 3.

Also, can you generally do an online check-in for a UK leaving flight even when you are in Canada (I can fly out of SEA as well as YVR) if you're within the 24 hour window. Both issues would increase the amount of time I need as a cushion between arrival and departure.

Is it possible to go from one international flight (from NA) and immediately go to your flight back home without having to go through customs, etc... I use either UA or AC, which are both housed in Terminal 3.

Yes, you simply have to clear security. You do not have to clear immigration or customs.

on the same topic, is it possible for someone from the uk to do this on an MR to the United States?

Also have any brit's on here ever done a MR to the United States? Do customs get 'funny' about it?

on the same topic, is it possible for someone from the uk to do this on an MR to the United States?

Transiting the US requires clearing US immigration and customs. So a UK-US-UK mileage run means presenting the passport to US DHS/CBP (i.e., immigration & customs).

Since this is in the new "Discussion" forum I think it would be appropriate to go slightly OT here.

How does one afford MRs through LHR given the incredibly high taxes?

Example, UA is running a ~$300 deal IAD-LHR, but the taxes are also ~$300. Not good for MRers!

Since this is in the new "Discussion" forum I think it would be appropriate to go slightly OT here.

How does one afford MRs through LHR given the incredibly high taxes?

Example, UA is running a ~$300 deal IAD-LHR, but the taxes are also ~$300. Not good for MRers!

The routes to the USA in my opinion are some of the best MR's from the UK. They cost an average of £300 return, earning an average 6000 miles or so dependant on destination / airline. I would really like to know if there were any better deals than this? (besides Australia as I do not have time to go there!)
We are very disadvantaged in the EU as their is high taxes through everywhere making MR's extremely difficult! Plus our airlines seem to be very stingey on handing out points on European flights. In order to re-qualify my star points it would probably be cheaper to fly to the USA and fly around a bit internally!

Anyone else from the EU on here who may know some good MR routes inside Europe?

... In order to re-qualify my star points it would probably be cheaper to fly to the USA and fly around a bit internally!...Seriously, you are absolutely right. I have a 6000 mile single day MR coming up next Wednesday that I paid $179 for.