Someone very close to me summed up his opinion of commercial air travel, mostly with U.S. airlines, this way: “Flying is harassment.”

While there can be little argument that there are many irritating aspects to flying — some of them, such as security checks, not being the carriers’ fault and others, such as the abuse of this United Airlines passenger reflecting tone-deafness among staff and senior management — there’s no denying that for investors, the industry has been very good in recent years.

Here’s a comparison of the 10-year performance of the S&P 1500 Composite Index (which comprises the large-cap S&P 500 SPX, -0.84% , the S&P 400 Mid Cap Index MID, -0.88% and the S&P Small Cap 600 Index SML, -0.78% ) and the airlines included in the index:

FactSet

As you can see, the S&P 1500 airlines industry group has had a much higher 10-year total return than the index, although the industry suffered more in the aftermath of the credit crisis of 2008.

But check out the five-year comparison:

FactSet

Once again, it hasn’t been the smoothest ride, but the airlines as a group have more than tripled the five-year return for the index.

Also see: United’s stock is falling 3.7% and wiping $830 million off the airline’s market cap

Here are three- and five-year returns for the nine airlines in the S&P 1500, through April 11:

There’s no five-year return for American Airlines Group Inc. AAL, -1.23% because the company was formed through the merger of US Airways and the “old” American Airlines parent AMR (which had gone bankrupt in 2011) in 2013.

Sales growth and buybacks

Here are two sets of numbers showing the “shareholder-friendly” way in which the airlines are being managed, starting with sales growth over the past 12 months:

It’s interesting that United Continental Holdings Inc. has suffered the biggest sales decline among the group over the past 12 months and that three of the “big four” carriers have reported sales declines, the exception being Southwest Airlines LUV, -4.03% .

But most of these airlines have been buying back enough shares to decrease their share counts considerably. This means higher sales and earnings per share:

All in all, a very impressive set of numbers.

Cheap

The S&P 1500 Composite Index trades for 16.2 times consensus 2018 earnings estimates, based on analysts polled by FactSet. Here’s how that compares to forward price-to-earnings valuations for the airline group:

So why are the P/E valuations for airline stocks so low? It probably springs from continued mistrust among some investors after the decades of losses, mergers and bankruptcies that followed the deregulation of the industry in the early 1980s. And it has only been six years since AMR went bankrupt.

Analysts are still positive on the industry, as shown by the majority “buy” ratings for two-thirds of the group (including United):

There are a lot of numbers backing up a positive outlook for U.S. airlines. As you can see in from the stock charts, even during a period of stellar overall performance, there can be plenty of volatility. But if you are looking for an industry group with decent or better growth of sales per share and don’t expect a severe recession, these stocks are worth a closer look.