A 14-year-old boy was rushed to Alder Hey Children's Hospital after being involved in a horror smash in Burnley.
Emergency services were called just before 3pm on Friday and the road between Burnley and Padiham was closed immediately.
The North West Air ambulance helicopter touched down on Ighten Mount Bowling Green.
The teenager, who was the pillion passenger on a scrambler bike, sustained injuries to his hand after being involved in a collision with a Ford Fiesta.
A 24-year-old man, who was riding the bike, was air-lifted to the Royal Preston Hospital having suffered serious leg injuries.
The driver of the Ford Fiesta was not injured in the incident.
The road remained closed until 7pm and Burnley Bus Company advised bus passengers of delays and diversions after the accident.
Police investigations are continuing and witnesses are being asked to come forward.
A spokesman for Lancashire Police said: "We are continuing to appeal for anyone who witnessed the accident to come forward and contact us on 101 log number 805."