Airports may also contain premium and VIP services. The premium and VIP services may include express check-in and dedicated check-in counters. These services are usually reserved for First and Business class passengers, premium frequent flyers, and members of the airline's clubs. <answer>Premium services</answer> may sometimes be open to passengers who are members of a different airline's frequent flyer program. This can sometimes be part of a reciprocal deal, as when multiple airlines are part of the same alliance, or as a ploy to attract premium customers away from rival airlines.
What type of services are sometimes open to passengers who are members of a different airline's frequent flyer program?
Premium services