At first blush, the first-quarter earnings at Grupo Aeroportuario del Centro Norte, known as OMA (NASDAQ:OMAB), don't look so great. Look deeper, and they don't get much prettier.

The Mexican airport operator, which counts the airports at Monterrey, Mazatlan, and Acapulco among its jewels, showed a very good passenger traffic growth of 14.5% for the quarter. That's no surprise to us, since we've pointed out that the engine of improvement has been the entry of new, low-cost airlines, which improved domestic traffic by 22.9% over the prior year.

The 5.9% drop in international traffic was less savory, despite OMA's airports being served by the likes of Alaska Airlines (NYSE:ALK), Frontier Airlines (NASDAQ:FRNT), AMR's (NYSE:AMR) American, Continental (NYSE:CAL), UAL Group's United (NASDAQ:UAUA), and Delta.

Also low on the spicy scale: a revenue increase that clocked in at only 10%, and net income that rose only 5.8% -- not that there aren't good reasons for these returns to diminish as we move down the income statement.

Management's explanation cites increased costs on a variety of fronts, from cold-weather-induced energy bills to upgrade costs at Acapulco and Ciudad Juarez. Results also suffered the inevitable switch in the technical assistance fee (paid by other Mexican airport operators as well) from a fixed fee to 5% of EBITDA.

The bottom line for U.S. holders of the ADS came to $0.22, the same as what they'd have earned last year (if the company had traded then).

You can't hear me, EVEN IF I SHOUT, but I assure you, I don't sound worried. When I first pegged OMA as a recommendation for Motley Fool Global Gains, some 26% ago, I figured it was a great long-term buy. I also expected lumps, since that's how the airport business works.

In fact -- and subscribers will have to forgive me for this -- I sort of wish the stock had endured one of those crazy market reactions to this less-then-stellar report. Long-term gains are great, but when you can juice them with an easy 10% to 15% pickup on a panic, they're even easier.

At the time of publication, Seth Jayson had no positions in any company mentioned here. See his latest blog commentary here. View his stock holdings and Fool profile here. The Fool has a disclosure policy.