Spirit Airlines posted a sale today with $39 one-way fares from LaGuardia to Detroit, Myrtle Beach, Fort Lauderdale and Orlando (fares are higher, but not much higher, to other destinations). The $39 fares were in a New York Times ad, but its website says fares start at $49. Even so, I couldn’t find any of those fares available. To sum, there may or may not be $39 fares from LaGuardia to the aforementioned cities. Happy trails.