US Transportation Tax is 7.5%. UA is showing the base price and then including a line item for the tax once you've made a selection. I feel like one of AA or DL used to do the same thing, but both now seem to be showing the all-in price. I think UA will probably have to switch to showing the all-in price also; I don't think the US government wants anyone to pay attention to the amount of tax wants consumers to be offered a lowball price and then hit with the total after making a purchase decision.