The top members of United MileagePlus can now enjoy Mercedes-Benz tarmac transportation service at San Francisco International Airport (SFO). The free service is offered to United’s Global Services members (an invitation-only group of high-value flyers) and United Global First customers who have close connections. The flyers will be met at the aircraft and driven to their connecting flight in a Mercedes-Benz GL350 BlueTEC SUV. United has a similar service in Chicago, Houston and Newark.