How long is the flight from Chicago to Glasgow?

A random search for flights from San Francisco (SFO) to Glasgow (GLA) shows:

OPTION 1: 13hr 35min via London Heathrow (LHR)
SFO - LHR BMI British Midland Airways Flt 4494 Dep 07:00pm 11Dec,Fri
Operated by United Airlines
LHR - GLA BMI British Midland Airways Flt 8 Dep 03:05pm 12Dec,Sat
Flight Duration: 11hr 55min; Layover Time: 1hr 40min; Total Trip Time: 13hr 35min