Great Lakes Reports May, 1999 Traffic; Revenue Passengers Carried up 22.9%

GREAT LAKES AVIATION REPORTS MAY, 1999 TRAFFIC; REVENUE PASSENGERS CARRIED UP 22.9%

Spencer, Iowa -- June 4, 1999 -- Great Lakes Aviation, Ltd. (NASDAQ:GLUX) today announced preliminary passenger traffic results for the month of May.

Scheduled service generated 21,322,000 revenue passenger miles (RPMs), an 11.5 percent increase from the same month last year. Available seat miles (ASMs) increased 14.2 percent to 44,504,000. As a result load factor decreased 1.2 points to 47.9 percent. The company carried 83,318 passengers, a 22.9 percent increase compared to May, 1998.

For the five months ended May 31, 1999 RPMs increased 26.6 percent to 98,751,000 compared to the same five months in 1998 while ASMs increased by 33.6 percent to 222,653,000 for the five months in 1999 compared to 1998. As a result, load factor decreased to 44.4 percent for 1999 compared to 46.8 percent for the same five month period in 1998. The company carried 379,412 revenue passengers for the five months ended May 31, 1999, a 42.0 percent increase compared to the same five months in 1998.

	May 1999	May 1998	Change
Passengers Enplaned	83,318	67,788	+22.9%
Revenue Passenger Miles (000)	21,322	19,131	+11.5%
Available Seat Miles (000)	44,504	38,967	+14.2%
Load Factor	47.9%	49.1%	-1.2 Pts.

	YTD 1999	YTD 1998	Change
Passengers Enplaned	379,412	267,243	+42.0%
Revenue Passenger Miles (000)	98,751	77,991	+26.6%
Available Seat Miles (000)	222,653	166,651	+33.6%
Load Factor	44.4%	46.8%	-2.4 Pts.

Beginning May 18th all Denver Embraer Brasilia flying was transferred to Chicago-O'Hare business markets. Service was discontinued in a number of South Dakota-Chicago markets as well as in a number of Nebraska, Iowa and South Dakota-Minneapolis/St. Paul markets. New routes at Denver in May included new service by Great Lakes to Hayden/Steamboat Springs and Gunnison in Colorado and to Amarillo, Texas. On June 1st Great Lakes added flights between Denver and Eagle/Vail, Colorado.

As of June 1, 1999, scheduled service was being provided at 70 airports in fourteen states with a fleet of eight Embraer EMB-120 Brasilias and 40 Beechcraft 1900Ds. A total of 312 weekday flights are offered at three hubs, 86 flights at Chicago-O'Hare, 208 at Denver and 18 at Minneapolis-St. Paul. In addition, the company operates 4 weekday round trip flights between Springfield, IL and Chicago-Meigs Field. All scheduled flights are operated under the United Express marketing identity.