There are four primary types of tankers today: the KC-135 Stratotanker, the KC-46A Pegasus, the Airbus A330 MRTT, and a few legacy Il-78s in service with some countries. Additionally, there is the newly developed Chinese Xi’an Y-20 tanker variant and the recently retired US KC-10 Extender tanker. Other aircraft, like the KC-130J, can provide probe and drogue refueling, but aren’t of interest here.