It depends on the time, the day and the airport. The total hassle to get on the plane is about the same now that European airports do the same screening for carry-on liquids. The security line may be shorter or the security check may be done as you’re boarding the plane in Europe, so that part is usually the same or better. If things get backed up I think they are less likely to do things to alleviate the problem (open another check-point, send people to a less busy check-point elsewhere in the airport or allow people with earlier flights through first) in Europe.

In my experience, European airports usually have much longer longer lines at check-in and baggage check. Try to check-in on-line or at a kiosk. I use the same “2 hours before flight time” as recommended for US airports.

Also double check your airports before you book your other flights. London has 3 airports and I have run into people that did not realize this when they booked non-refundable flights. You can google the airport and find out all the information you need to know. Also be sure to check the airline web site. Many airlines have a cut off time that can be 1/2 hour to 1 hour prior to departure.

On my last trip, I found myself with a disappointingly large amount of extra time at each airport I was at. I wouldn’t recommend NOT showing up early, but I stuck by the typical “two hour early” rule, and ended up with about an hour and forty five extra minutes each time. I’m sure it varies, but hell even when I was at super-busy airports we always seemed to get through very quickly.

That said, I have never had to check bags or anything. And I’ll also note that each airport seems to have different “rules” and “protocol” as to what hoops you have to jump through; some make you take off your shoes, some don’t… others make you practically strip search going thru metal detectors, others just wave you through.

I have to say also that I don’t trust their ability to “protect us” 100% after last year either. My friend and I were both carrying in 250g canisters of tobacco for our friend who was putting us up for a few days. Both were in metal canisters, and I fully expected to be asked about it as I went through. Well, mine went down the belt with no incident, but my friend’s bag lit up the line like a christmas tree, after which they tore open his bag and dug through all his stuff, and interrogated him about the tobacco. Meanwhile they didn’t even notice mine… so it makes you think how closely they’re really looking sometimes, at the least.