for narrow body, it's Southwest Airlines....at least in the US.
The pay isn't based on hours, its called a 'trip' (essentially based on distance), and each flight is paid for a specific number of trips. There are some rigs that make up for delays, cancellations, extra flying, move-up pay, reassignment pay and whatnot.
average trips per month are around 100.
Airline Pilot Central - Southwest | Major-National-LCC
check that out to figure it out. Some pilots have pulled in upwards of 130 trips in one month, the record being 344. That guy got about 50000 USD in one month.
Working extra at SWA isn't that hard, and the benefits are VERY generous, as well as quality of life overall.