In the air
A business jet and an airliner cruise at similar speeds. Some business jets fly a little faster and higher, above most airline traffic, which can shorten routings and avoid holding. On a trip like London to Nice the flight itself takes 1h 43m of block time on a midsize jet, close to an airline schedule.
On the ground
Airlines advise arriving up to two hours before an international flight. At a business aviation terminal 15 to 30 minutes is usual: security and passports take minutes, and the car often drives to the aircraft. On arrival there is no baggage belt; the bags come off with you.
Closer airports
Private jets use smaller airports that airlines do not serve, closer to the destination: Farnborough or Biggin Hill instead of Heathrow, Le Bourget instead of Charles de Gaulle, Samedan for St. Moritz, Olbia for Porto Cervo. The drive at each end is often shorter than the flight.
