AirPlus International customers during the first quarter spent 8 percent more on business travel year over year,

according to a report released Tuesday by parent company Lufthansa. Clients' air travel spend rose 7.5 percent, "with companies booking 7.3 percent more business flights," according to the report. Lufthansa for the first quarter reported €16 million (US$18 million) in AirPlus earnings before interest and tax,up 50 percent year over year due to international business travel growth and "positive exchange-rate effects."