[zwily]

I recently flew SLC-CLT and CLT-SLC, and both flights were DL2070.

[madcaptenor]

I've also seen this on Delta on ATL-PHL. I had guessed it was limited to relatively short flights - because why waste a number on a short flight, and because there's less room for irregularity where you end up with both flights in the air at the same time - but it looks like at least SLC-CLT on Delta and DFW-SEA on American do it.