Up-and-coming Eastern European player CSA Czech continues to thrive, and is releasing a host of promotions for members of its OK Plus frequent flyer program this summer.

Effective July 1, members will be able to redeem miles for car rentals with Sixt in the Czech Republic. Members can cash in from 15,000 to 70,000 miles, depending on the category and period of rental. OK Plus members can also get a free upgrade voucher from Avis for online reservations made through CSA’s Web site through Aug. 31.

Czech has also re-opened its lounge at Prague, with extended capacity for 170 passengers.

On the hotel front, OK Plus members can take advantage of double miles and up to 40 percent off stays at Sofitel hotels worldwide through Sept. 6, and 250 miles per stay and up to 50 percent off at Novotel and Mercure hotels.