There's been a big boom in small, regional jet airlines over the last few decades (Low Cost Carriers, or LCCs, sometimes known as Low Cost Regional Carriers). A

There's been a big boom in small, regional jet airlines over the last few decades (Low Cost Carriers, or LCCs, sometimes known as Low Cost Regional Carriers). A lot of companies saw what Southwest and JetBlue were doing and figured they could do the same on a smaller scale: control costs by flying limited routes and serving smaller markets, where they could outcompete the bigger carriers on price [1]. Then, if things went well, maybe expand from there. It's an incredibly crowded field now, and even many of the LCCs themselves collapsed. [1] It seems a little counterintuitive, but in the airline business, there is almost a reverse economies-of-scale effect. This is because routes can't be flown on demand, but must be scheduled, and so you're maintaining a fixed supply while dealing with variable demand. You don't have a lot of fantastic levers to pull to deal with fluctuations in real time, because you can't redirect inventory (planes, crews, etc.) on demand, and canceling flights causes chain reactions across hubs and spokes. This is why a lot of the big carriers have been cutting flights and routes like crazy in recent years. Faced with undersupplying or oversupplying the market -- and faced with all their other enormous costs -- they'd rather bet on undersupply. Passengers these days aren't incredibly loyal to any given airline, and they're very price conscious. They won't give you credit for having a bigger network; all they care about is getting from A to B right now, and finding the best price in so doing. So having a bigger network can often be a liability.