Past the airport, the route turns north near Hanoverville and leaves Airport Road. After a short distance, PA 987 intersects Route 329 and forms a concurrency with the route northeast to Bath. Just west of the borough center, the concurrency ends at Route 248, at which Route 329 ends. PA 987 continues north into Chapman, turning to the northwest and terminating at an intersection with Route 946 in Klecknersville.
PA 987 was originally given to the portion of the road between Portland in Northampton County and the New Jersey border at the Delaware River. This alignment remained in place from 1928 to 1936. Four years later, the designation resurfaced at its current location.
The southern terminus was relocated from Union Boulevard in Allentown to US 22 in 1955.