Topeka ? Six months after United Airlines began flying to Chicago out of Topeka Regional Airport, ridership is increasing but airport officials say it needs to continue climbing.

Airport authority president Eric Johnson says the twice-daily flights to Chicago were about 64 percent full in June. The Topeka Capital-Journal reports the numbers increased from 25 percent full in January to 65 percent in May.

Government funds provided about $2 million in revenue guarantees if ticket sales fell short of a revenue goal. Johnson said most of the guarantee funds probably were used in the slow first quarter and the revenue shortfall for the second quarter hasn’t been calculated.

He says airport officials want the service to be profitable to ensure that United wants to continue to provide service from Topeka.