First, jets aren't sexy. They're obnoxiously loud and stupid fast, but they are not sexy. All angles and sharp edges. Not sexy.
Someone said the Corsair. Have you ever seen one up close? Huge snout. Again, not sexy.
ME262? Looks like a lizard with wings.
A10 Warthog? Sure...
For an American design, the P51 is admirable. The damn airscoop is odd-looking, but distinctive. But no.
They sexiest aircraft ever produced has to be the Supermarine Spitfire Mk. IX. You could make arguments for other variants, but I like the Mk. IX. If the lines don't win you over, the Rolls Royce Merline will. I've only seen one fly on two occasions, and they were religious experiences. The second time was in formation with an Avro Lancaster and Hawker Hurricane. Beautiful.