According to Goolsbee and Syverson, How Did Incumbent Airlines Respond

Multiple Choice

According to Goolsbee and Syverson, how did incumbent airlines respond to the entry of Southwest Airlines?

A) They raised airfares just before Southwest's arrival and then cut airfares when Southwest began operating.
B) They lowered airfares just before Southwest's arrival and then raised airfares when Southwest began operating.
C) They began cutting airfare as early as 1 to 2 years before Southwest began operating from the same airport.
D) They kept airfares unchanged before Southwest's arrival and then lowered airfares when Southwest began operating.