Simplify the following text for a Grade 4 native English-speaking person.
Original: Launched later than the competing Boeing 707 , the DC-8 nevertheless established Douglas in a strong position in the airliner market , and remained in production until 1972 when it began to be superseded by much larger designs , including the DC-10 and Boeing 747 . The DC-8 design allowed it to hold slightly more cargo than the 707 .
Simplified: It was launched later than the Boeing 707 .