Air-travel prices have gone up in several Florida markets. United Airlines announced Thursday that prices for one-way tickets to Florida would increase by $10, except for flights that are on sale. American Airlines, Delta Air Lines and Southwest Airlines imposed fare increases on several of their Florida routes soon after. US Airways attempted a $10 increase of one-way airfares on a wider portion of its domestic market, but it reversed the increases Monday on all fares except those for Florida.