This is an exchange that happened ... on a trip from Las Vegas (Henderson) to Oklahoma City (Sundance Air Park). We were level at 15,000 and just handed off from Las Vegas TRACON to LA Center. We had been at 15,000 for a few minutes and were definitely hungry to get to our final altitude of FL270. The busy airspace due to a NASCAR race complicated matters for everyone.
Starship XXXX (me):
"LA Center, good afternoon, Starship XXXX level at one five thousand, direct cowboy, looking for higher."
"Starship XXXX, LA Center. Maintain one five thousand MD-80 traffic in your six o'clock position in a very slow climb. I need to keep you at one five thousand until clear of traffic."
"LA Center, Starship XXXX, maintain one five thousand.
"LA Center, Starship XXXX, no contact with traffic."
ZLA (without missing a beat):
"That's the idea."