American recently announced that it was launching a trial of something called One Stop Security (OSS). If you are coming from London/Heathrow and connecting through Dallas/Fort Worth, you will be able to use this service. Further, you don’t need to collect your checked bag but rather get a picture of the bag on a screen for you to confirm it’s yours. In other words, you should still look to avoid connecting in the US if you’re a foreign national. If you think about the rest of Europe, you need to trust the security process of every country in the Schengen Area.