I have 1 hour 45 minutes to transfer from BA (Terminal 5) to AA (Terminal 3). It hadn't dawned on me that these Oneworld Alliance airlines operate sometimes out of different terminals (half the US destinations including O'Hare currently depart from T3). Does this mean UK immigration is required in this Asia origin to North America destination transfer?
Immigration no; security yes.
Is it one ticket?
I like the video. So what is really involved? How can a person take a train that continues on to London and not go through immigration?
Yes it's one AA ticket, homebound so not really concerned if the luggage is late. Award ticket return choices from Amman or Tel Aviv are pretty crappy.
Edit: I see, there's a shuttle bus that works airside to avoid immigration. https://www.youtube.com/watch?v=f-4sVZRpwow
So if landing at 5B or 5C a person first has to take the transit train to 5A and then the shuttle bus from there to T3.
The train between T5 an T3 must require immigration.
I was going to say it must be an airside bus. The inter terminal trains (Heathrow Express and tube) are both landslide.
There is a dedicated bus for airside transfer between T5 and T3. You follow signs to “flight connections” to reach it. You will go through security again in T3.