Selena Gomez & Cara Delevingne -- Just a Friendly Pap Crush (VIDEO)

Selena Gomez and Cara Delevingne are back from their sun-drenched trip to St. Tropez and when they arrived at LAX Thursday ... they received a welcome home crush.

The pair, now famously photographed hanging on a yacht in their bikinis and showering together, are the hottest "couple" around these days ... even if they aren't ... ya know. Selena was nuzzling with a muscly guy during the trip.

Anyway, they were bombarded with questions about their friendship, but they remained tight-lipped.