Delta Air Lines (NYSE:DAL) shareholders have earned a 21% return over the last year

We believe investing is smart because history shows that stock markets go higher in the long term. But not every stock you buy will perform as well as the overall market. Unfortunately for shareholders, while the Delta Air Lines, Inc. (NYSE:DAL) share price is up 20% in the last year, that falls short of the market return. Having said that, the longer term returns aren’t so impressive, with stock gaining just 11% in three years.

So let’s assess the underlying fundamentals over the…