Last week, Lyft unveiled its public offering prospectus, which showed that the company was growing quickly but was also losing money. Airbnb has turned a profit, excluding certain costs, for the past two years, the company said in January. Airbnb is also locked in competition with Booking Holdings. Buying HotelTonight gives Airbnb access to even more properties. Airbnb said HotelTonight would continue to operate as a stand-alone business.