In news of U.S. airports, Seattle-Tacoma has reportedly expanded the availability of TSA’s PreCheck expedited security option to more travelers; Miami International has become the second airport where American Airlines offers its Flagship Check-In service for premium passengers; a new company launches a web site for comparing and booking airport parking; and U.K. media warn that travelers to London Heathrow could be facing major arrivals bottlenecks as the Olympics near.

• The Transportation Security Administration announced several weeks ago that participating Alaska Airlines frequent flyers can now access TSA’s PreCheck expedited security screening option at Seattle-Tacoma, but the Seattle Times is reporting that the PreCheck option there has been expanded so that it is now available to participants from four other airlines as well, including American, Delta, United and US Airways. The TSA PreCheck lane at SEA is located at Checkpoint 5 in the north end of the Sea-Tac terminal.

• American Airlines said it has expanded its Flagship Check-In service for premium passengers to a second airport, Miami International (the first is at Los Angeles International). It’s available from 4 a.m. to 11 p.m. daily, and is in Concourse D of the North Terminal. With Flagship Check-In, AA premium customers get a separate security line as well as a “private, expedited experience with customer service representatives” who can help with things like baggage, seat and itinerary changes, connecting flight information and more. Passengers eligible for Flagship Check-In include ConciergeKey members; customers of AA’s Five Star Service (a one-on-one airport assistance plan); first class passengers flying on a MIA-LAX three-cabin aircraft; and first class passengers flying on an international outbound flight of American or select Oneworld partners. For details, go to www.aa.com/flagshipcheckin.

• A new airport parking reservations website has been launched at http://airportparkingworldwide.com by two partners, Route 72 Systems and Travel Time LLC. Users simply enter the selected airport, departure and return dates to see what’s available and what it costs at nearby long-term parking lots. The fledgling operation said it “already has more than 10 airport parking locations on board,” and is making “a big move” to add locations near the Newark and Los Angeles airports.

• With the London Olympics only weeks away now, U.K. newspapers are reporting that visitors arriving at London Heathrow could be in for a nasty surprise, in the form of ridiculously long waiting times to clear Immigration. They even quoted representatives of LHR operator BAA as admitting that wait times are exceeding its rather generous “target times” – 45 minutes for non-EU arrivals and 25 minutes for Europeans. The U.K.’s Daily Telegraph reported that in recent days, some arrivals had to wait almost two and a half hours at LHR’s Terminal 4 to clear immigration and customs formalities. The U.K. government reportedly has plans to add more inspectors before the Olympics crunch begins, bringing an estimated 650,000 extra passengers into Heathrow – in addition to its usual numbers.