Not exactly, the USPS uses a contractor at airports to sort their registered mail before it gets sent to fedex where they fly it and sort it at fedex hubs then it gets returned to usps at city airport destinations. From the an express clerk sorts and delivers. So you can pay extra for fedex overnight or ups first day air but the usps service you get is nearly all fedex, just a different truck and uniform. If there is room in an airline can they fill it with first class because usps pays fedex by the can. Ups also transports some usps mail as do all the airlines. Most long haul is contracted and many distribution trucks are contractors. Its practically only a delivery and collection service at usps now. Letters are a different story, nobody can touch usps letter delivery and turn a profit.