Two unexpected things happened with airlines in May. Cancellations were the 3rd lowest ever and planes left and arrived on time, according to the Bureau of Transportation Statistics.Related: 6 AIRLINE STOCKS WORTH CONSIDERINGLeadersOf major airlines, Delta Air Lines Inc. (NYSE:DALC) came out on top with just 39 cancellations for the month. Statistically, that’s a zero. Alaska Airgroup Inc. (NYSE:ALKC) cancelled only 0.2% of its flights and Hawaiian Holdings Inc. (NASDAQ:HAC), aka Hawaiian Airlines shut down just 0.3% of its scheduled flights during the month.According toDelta CEO Ed Bastian, the airline had 77 days in April, May and June with no cancellations whatsoever in its “mainline” operations. Mainline operations do not involve regional carriers.LaggardsAlthough May cancellations were the 3rd lowest ever, not everyone made a contribution. Low cost leader, Spirit Airlines Inc. (NASDAQ:SAVEC) cancelled 1.4% of its flights. This was not positive publicity for the bargain end of the airline spectrum.Regional carrier, ExpressJet Airlines, which operates flights for American Airlines Group (TSX:AALD), Delta and United Continental Holdings (NYSE:UALD) dropped 1.1% and Virgin America Inc. cancelled 0.7% of its flights in May.On Time (Almost)As for punctuality, flights that land within 15 minutes of their scheduled time are considered “on time.” Overall in May airlines were on time 83.4% of the time. This was down slightly from April but up from May a year earlier.Hawaiian was the most punctual at 92.1%. Alaska was next at 90.3% and Delta rounded out the top 3 at a 88.6% on time rate.Late To The DanceSpirit’s on-time rate of 76.4% made it the “late leader.” Virgin America was next closest at 76.4% and Frontier Airlines came in 3rd with an on-time rate of 80.2%.The news was especially bad for Spirit and for Virgin America, both of which also made the list for more cancellations in May.Related: WHEN THE NEXT RECESSION HITS …Why Punctuality Matters To InvestorsIt’s likely obvious why being on time and not cancelling very many flights matters to consumers. Nobody wants to arrive at the airport only to find their flight has been cancelled and when a scheduled flight is late arriving, your multi-leg schedule can be upset, resulting in delays and even unintentional overnight stays.On the investor side, it’s all about profitability. Guess what drives profitability? Flights that take off and land as scheduled with full loads of paying passengers. It’s hard for that to happen if people stop flying a particular airline because it cancels flights and doesn’t land on time.Beyond PunctualityAccording to The Harvard Business Review, however, there’s more to the profitability picture than being on time. There’s the “upmarket.” Simply put, any business that doesn’t pursue the the next highest margin consumer, is doomed to fail.From an investor’s viewpoint, it pays to look for not only airlines that do their best to service the customers they have but those that seek to attract those who will turn out to be more profitable.The HBR suggests the natural growth cycle would be from low-cost offerings, to regional, to national to international.