(MONEY Magazine) – Hotels are being built alongside or even perched atop airport terminals -- mostly because getting in and out of airports has become a trip in itself. The Denver airport slated to open 18 miles from downtown in 1993 will include one. And Boston is trying to shoehorn an in-terminal hotel into remodeled Logan Airport. The advantage, of course, is convenience. With the hotel lobby in the airport concourse (two in Texas that are adjacent to terminals, though, require short shuttle rides), it's possible to book a room for a four-hour (or longer) layover to nap, shower, hold a meeting, hook up the laptop or whatever -- all in complete privacy. The cost for such a stay is typically 50% of the overnight rate. At many of these places, you can even work out at the health club, swim or get a haircut. So far, the U.S. has seven such hotels: -- Dallas/Fort Worth Airport: Hyatt Regency (800-233-1234), 1,400 rooms; night, $120 to $150; day, $75. -- Houston Airport: Marriott (713-443-2310), 560 rooms; night, $109 to $130; day, $55. -- Miami International: Hotel MIA (305-871-4100), 260 rooms; night, $99 to $175; day, $45 to $55. -- Tampa International: Marriott (813-879-5151), 292 rooms; night, $130 to $155; day, $69. -- Bradley International in Hartford: Sheraton (800-325-3535), 237 rooms; night, $125 to $149; day rate will be given upon request. -- Detroit Metropolitan: Marriott (313-941-9400), 162 rooms; night, $114 to $135; day, $50 to $90. -- O'Hare International, Chicago: Hilton (312-686-8000), 885 rooms; night, $105 to $135; day, 50% of the lowest available rate that day.