Langkow's end-to-end rush and backhand shot past Devan Dubnyk 4:44 into the second period broke a scoreless tie and Aucoin doubled the Phoenix lead with a power-play goal 13 1/2 minutes later.
Mike Smith turned aside 24-of-26 shots to earn the victory.
Rookie Ryan Nugent-Hopkins netted his sixth goal and Theo Peckham also scored for Northwest Division-leading Edmonton, which lost for only the third time in 14 games to start the season.
Dubnyk finished with 26 saves for the Oilers.
Toddler uninjured after being knocked over by Obama family dog
Gal Gadot cast as Wonder Woman for 'Batman vs. Superman'