I'm just trying to get a handle on how this all works. I have roundtrip tickets from NY to Heathrow. From London, I will be flying to Munich, and eventually fly back to London from Zurich. I'm curious as to what point in my journey I will have to deal with the customs/immigration people. Specifically..

1)If I don't leave Heathrow and transfer to another airline, will I have to go through customs/immigration?

2) If I fly out of Gatwick I assume I go through it at Heathrow, regardless of whether I am staying in London that night or not, right?

3) Will I deal with it in Munich or Zurich, or my trip back to London?

One last question (for now): How early before these intra-Europe flights should I plan on being at the airport?

I suspect you'll have to deal with Immigration/Customs when you enter Switzerland.

Will you be transferring to another airline in the same terminal at Heathrow? (which may not make any difference..others will know for sure).

Yes, if you leave Heathrow for anywhere within the UK (to include Gatwick) you'll have to go through C/I.

As to how early to arrive I would check on the individual airline (being used) site for THEIR recommendations.

Basically, whenever you change countries and leave the airport/train station, you will have to go through Customs. When you get to Heathrow, will your baggage be transfered to your next flight, or do you need to pick them up first? If you pick them up and then check into your flight to Munich, you might also go through Customs then. Just be prepared to wait in a long lines while the EU citizens breeze through waving their passports.

Is that a true statement above? (I'm not arguing, really just asking.)

Because I don't recall goind thru customs when I took the train say from Geneva to Venice, or from Venice to Paris... and that was certainly changing countries.

I'm kind of surprised too. I didn't expect to have to pass through customs across every border.

I'm afraid I can't answer the questions regarding terminals or luggage, because I'm still working on the logistics and haven't made any further flight arrangements. I assumed if I book two airlines separately that I would have to pick up my luggage myself. I have since read that it may be possible to check it through, but that makes me a little nervous. If it gets lost, I imagine I'll have two airlines pointing fingers at each other.

Suze...every train leaving Brig for Italy usually has Italian Immigration officers board just after the Simplon Tunnel and then they walk through the train and get off in Domodossola.

I have yet to enter Switzerland and not had some sort of Immigration/Passport/Customs check.

IF your bags are checked through to Germany, on arriving and departing from Heathrow you will remain "airside" during the transit - no passport control, no customs inspection. However you will be subject to a security check when you go from one terminal to another. When you arrive in in Munich you'll do both.

If you arrive at Heathrow and fly out of Gatwick, you'll clear both immigration and customs (having claimed your bags) at Heathrow, since you'll officially be in the UK while transiting to the other airport.

On the way back, IF your bags are checked through to NYC (again, assuming no LGW-LHR transfer) then you can do the same thing at Heathrow - no immigration or customs inspection, just security. You will clear US customs and immigration in NYC.

I strongly recommend NOT setting up an itinerary that requires the Heathrow-Gatwick transfer. Serious PITA.

Two hours is ample transfer time at LHR; I'd never do a LHR-LGW transfer with less than 5 hours leeway. Checkin times are same as in N. America; some counters at LHR don't accept bags until 3 hrs before flight time.

I understand immigration and passport checks at the borders.

I thought this question pertained to customs, like "what's in that suitcase?" kind of a check.

Yes,Suze is right. I'm sorry if that wasn't clear. I was asking about the time-consuming, suitcase-checking, picked-the-wrong-line again ritual.

Which I never recall happening on a *train* trip at border crossings or arrivals in a new city/country...

Ok, let's try this again because I'm still unclear...

Let me start with specifics, because I think I know what I want to do: I am landing at LHR at 7:30am (Virgin Atlantic) and looking at a Lufthansa flight at 11:05 to MUC. (There is a British airways at 9:15, but I think I'd be safer with the later one). Coming back there is a BA flight from ZRH to LHR that arrives at 12:20pm and my flight back to NY leaves at 2:00pm.

Keeping in mind that it's different airlines and different tickets so it's my fault if I don't make it, is this doable?

I don't yet know if my bags will be checked through and I'm still not sure what impact that makes on customs/immigration if there are or aren't.

If I understand this right, if they are checked through, I would simply transfer from one flight to the other and go through immigration at MUC. Coming back I'm leaving from a non-Schengen and arriving at a non-Schengen, so I would assume I would have to Customs and Immigration both in LHR and back in NY.

If my bags are not checked through, does anything change?

Basically, what all this boils down to is how much time should I allow between flights with my bags checked through, and again without?