Hi,
I am flying into Heathrow from the US and then changing planes and flying to Cairo in the same terminal. Will I have to go through customs and get my bags and put them back in again before flying to Cairo? Thanks in advance.
Do you mean Customs? Or passport control?
Is this one ticket or two separate tickets? What airlines?
If this is one ticket, your bag should be transferred automatically to your second flight and you won't have to go through immigration or customs.
Go to this website, fill in your flight information, and you will get step by step directions: