How do flight transfers work?

[Mushroo]

This is probably super obvious but I’ve looked on the airline website and I can’t seem to find it.

Looking at flying Manchester to Chicago via London with BA.

when I arrive in London what happens? Do I go straight to the gate for the Chicago flight or do I have to go through passport control, collect baggage and go through security again? How long should I give myself? (It’s about 2.5 hours gap I think between the arrival and departure).

If the first plane is delayed and I miss the transfer, do BA sort it out? (It’s a package holiday with BA, but I think one of the flights might be operated by American Airlines).

thank you!

@Mushroo

you go through the transfer section and security again.
your bags should be tagged through ( pa that doesn’t happen in transferring in USA you need to clear at first port of entry).
if a connection is delays and same airline on same ticket BA will take care of any issues due to late arrival. In theory.

Companies often share flights so it is quite normal to buy one company's flight and actually fly with another. ( I think it might be called codesharing?)

Transfers as pp said have their own separate transfer areas to use. They are clearly marked and usually color coded.
When you get off your first plane look for transfer/transit signs.

(Welcome to Chicago)

When you check in at Manchester your bags will be tagged
LHR - Heathrow
ORD - Chicago
as long as both flights are on the same ticket. Useful to check this.

At Heathrow you will probably do security (this isn’t the case at all airports) but no passport control as you haven’t left the country and this is arrivals only (so you will do it in heathrow on the way back). You will stay “airside” so when you arrive you look for transfers not arrivals. You really don’t want to end up arrivals then go through the departures security again.

ba/aa will sort you out on another flight if you miss it. Flights do occasionally get held for a few minutes if they know that an incoming connection is running a bit late.

Ps 2.5 hours should be relatively relaxed, Even if your first flight is up to an hour late.
however ideally both flights arrive and depart terminal 5. If you have to change terminals then that is more faffy. I think there is an airside bus. I have done 1 h connections at terminal 5.

Thank you everyone. It’s mainly the outbound flight causing me concern but sounds as though it should be ok (in theory!). I feel much happier knowing I do a ‘transfer’ rather than having to essentially leave airside and do the whole thing again.

On the way back I’m super relaxed, if anything goes wrong I can manage getting from London to Manchester by other means 😂