While cruising at flight level, we heard the following between an American Airlines airliner and Miami Center:
"Center, American XXXX looking for higher."
Miami Center (female voice):
"Didn't hear you check in."
"First time I've heard your voice. I must've forgotten."
"That happens when you're over twenty-six or -seven."
"I hope you're talking thousands of feet."
Des Moines, Iowa