That’s right, today’s the day that a U.S/EU open skies agreement goes into effect. While there are a lot of interesting aspects to it, the biggest item by far is that it opens up access to London’s Heathrow Airport. Under the previous Bermuda II deal between the U.S. and the U.K., only two U.S. (United and American) and two British (British Airways and Virgin Atlantic) could fly to/from the U.S. from Heathrow, and then only (with limited exceptions for British carriers) from cities that had non-stops to Heathrow when Bermuda II was negotiated back in the 1970s.

Translation: US Airways, Delta, Continental, and Northwest will finally be allowed to fly to LHR. And American and United can fly to Heathrow from more places than they could before, including, for American, from RDU (service starts today). Heathrow is very runway capacity contrained, so this is all theoretical, unless an airline has or can get landing and takeoff slots. And those cost maybe $50 million to $60 million for the set, if they can be had at all.

So when does CLT get service to Heathrow? Glad you asked. US Airways previously had a single flight each day to London’s Gatwick Airport from Charlotte and Philadelphia on a 288-seat Airbus A330-300. The airline has been able so far to acquire Heathrow slots for a single flight. To no great surprise, it will be to/from Philly. Charlotte, for now, will continue with Gatwick service as before.

Might be tempting to think that this means CLT gets a LHR flight whenever US Airways can get ahold of another Heathrow slot. Not so fast: Check out the flight times on the new PHL-LHR-PHL flights. The return flight leaves Heathrow at 12:50pm and arrives at PHL at 4:00pm, which works with US Airways’ other flights from Europe. A little less appealling is when the flight over leaves Philly: 10:45pm (it arrives in London at 11:05am). So basically, it US Airways can get an earlier set of arrival and departure slots, then a second, earlier, another PHL flight is likely. If they can get times than are roughly similar to their current LHR times, then flights to and from Charlotte are possible.

Bonus observation: So far, about half of US airline’s Gatwaick service is moving over to Heathrow. Charlotte is the most significant hub that hasn’t seen a transfer of flight(s) to Gatwick. Service won’t all move over, as Gatwick is within 757 range from the northeast. US Airways, for example, is using a 190-seat 757 to Gatwick from Philly to suppliment its Heathrow flight.