Airline stocks are soaring.

Delta Air Lines, American Airlines and United Continental are up sharply this week, boosted by Delta which raised guidance for the first quarter, citing lower nonfuel costs and projecting higher per-passenger revenues. The major carriers are up 10%, 7% and 6%, respectively, since Monday. The move is prompting options traders to double down on one of those names: American.

"American Airlines did see about three times the average daily [call] volume today, and by far and away, the May 38-calls were the most active," "Options Action" trader Michael Khouw said Wednesday on CNBC's "Fast Money."

"Over 45,000 of those traded in all. That included the purchase of a block of 9,000. Somebody paid 35 cents for that block, and those are bullish bets that [the stock] will be above that $38 strike price by May expiration, which is about six weeks away," added Khouw.

Since each options contract is worth 100 shares of stock, this trade equates to a $315,000 bet that American Airlines will be trading above $38.35 by May expiration, or up about 13 percent from the current price.

If American Airlines were to race back up to those levels, it would represent a remarkable turnaround in the stock's fortunes. Between Feb. 26 and March 26, the stock plummeted 16 percent and wiped out nearly all of its year-to-date gains.

American Airlines was slightly higher Thursday.