ı applied UK visa with advance parole. but transit visa is kind of something different than if you have valid residency in us or not. even though you have US visa let’s say you get British airway to London and another air company to out of London then you need UK visa even tho you have valid visa for US. but if you have valid US visa and travel 3.location via British airways and as long as it’s same terminal, you don’t need transit visa neither on your way to 3.place or to US

where are you planing to travel? and the air companies ?

@Ivan b sorry I didn't get any notification of your response. was gonna travel to Africa through Amsterdam and back to the US through London. Delta keeps telling me that I'd need an airport transit visa unless I have a visa or green card. both embassies say if I have a US visa then I don't need a transit visa however, the airline has the final say on who they let on board. what I have is AP which I believe is a form of visa. it was a lot of confusion and I didn't want to be stranded in transit so I cancelled the flight and booked another that will transit within the US. Thanks a lot for your input

if you are passing through Any European country you will need a valid transit visa along with your AP to board. Don’t book a flight passing through Europe to any African country unless you have the transit visa solution 1, and the second options is you can travel to any African country only with your AP if your flight don’t land or connect through Air France or any European country. Kenya or Ethiopian airlines usually do those routes without touching Europe.