Passenger airplane getting ready for flightgettyFall isn’t in the air yet here in South Central Texas, but the season is often associated with something else: stronger performance in airline stocks.Looking back over the past 20 years, airline equities have tended to outperform in the final three months of the year, with the NYSE Arca Global Airlines Index gaining over 3% on average in October; this is followed by an even stronger showing in November and a 3% increase in December on average. According to the ...