The Boeing 767 was developed alongside the 757 with the intent of creating a narrow-body and a wide-body airliner that could share the same flight crew. Boeing achieved this, and a flight rating in one allows you to fly the other. This unique idea gave Boeing an interesting position in the industry, providing a family of aircraft that had a broad range of passenger capacities. The 767 quickly found its way into the airline world, and nowadays you'd be hard pressed to not see one fly into a mainstream airport.