Corporate airfares are on the rise while hotel rates continue to slide, according to American Express, reporting on first-quarter results of the rates actually paid by clients. According to the travel management company, international airfare increased by 3 percent over the first quarter of 2009, while domestic airfare posted a year-over-year hike of 6 percent. Results also revealed a slight increase in the percentage of travelers flying in international business class (41 percent, from 39 percent). Previous to 2009, the split between economy and business class for international travel typically was close to 50/50. Hotel rates continued to lag, however: International booked rates slid by 0.5 percent over last year, while domestic rates fell by 5 percent in the first quarter.