The service costs about $100 per round-trip and uses nine-seat Cessna planes.
"Apparently, this is quite a busy route for people doing business in Baltimore, and vice versa," Haynes said.
In March, Cape Air flew 245 one-way flights between Hagerstown and BWI and had 507 passengers, counting each one-way trip separately, according to data provided by the airline. That averages about 2 passengers per trip.
February's average was 2.2 passengers per flight and January's was 1.6 per flight, the data shows.
Those statistics are down from last August, when airline officials reported 636 passengers, with an average of 2.6 per flight.
Hagerstown Regional Airport Business Development Manager Greg Larsen said then that passenger counts varied from flight to flight, with some full and some empty.
Cape Air began its commuter service between Hagerstown and BWI on March 24, 2009.
The service is part of the Essential Air Service program, which provides a federal subsidy to link rural communities with larger hub airports. Cape Air receives $1.2 million a year from EAS for serving Hagerstown, airline officials have said.
Cape Air schedule beginning April 8:
Hagerstown to BWI:
Departs 6 a.m. Arrives 6:42 a.m. (except Sunday)
Departs 10:45 a.m. Arrives 11:27 a.m. (daily)
Departs 12:48 p.m. Arrives 1:30 p.m. (Monday and Friday)
Departs 3:15 p.m. Arrives 3:57 p.m. (daily)
Departs 5:20 p.m. Arrives 6:02 p.m (except Saturday)
BWI to Hagerstown:
Departs 9:45 a.m. Arrives 10:23 a.m. (except Sunday)
Departs 11:50 a.m. Arrives 12:28 p.m. (daily)
Departs 2:15 p.m. Arrives 2:53 p.m. (Monday and Friday)
Departs 4:20 p.m. Arrives 4:58 p.m. (daily)
Departs 8:20 p.m Arrives 8:58 p.m (except Saturday)