UA: LAS - FLL $139 RT 2.7 to 3.3 CPM (PQM)
Found some quality discounts on two different United routes landing your PQM cost per mile between $0.027 & $0.033.
Easiest route is LAS - FLL round trip with zero days stay.
4374 PQM @ $138 - $144
Next is LAS - FLL - IAD - LAS multi-destination with zero days stay.
5153 PQM @ $138 - $144
Available flights in April, May & August to the extent that I checked.