One axiom of the airline industry over the past several years is that if airlines can find a way to automate something, they will.

It’s not just that they’re pushing travelers to book online, but check-in is increasingly at kiosks, automatic re-booking programs deal with canceled flights and some airlines are even starting tag-your-own-bags programs. Travelers won’t even need to see an agent to check a bag — they can pay at a kiosk, get the tags, affix them and drop their luggage off.

Presumably, airlines will need one person to monitor the bag drop off. But, the message is clear — we’re trying to do this without humans.

This change clearly gives travelers fewer options, but it’s often worse for airlines, too. Here are a few examples.

On a recent trip to New York, weather back East was delaying most flights from San Francisco to Newark from two to five hours. Hundreds of people were trying to waitlist on earlier flights. At about 1 p.m., I discovered a 10 a.m. flight that hadn’t left yet. We went over to the gate; not only were my husband and I able to get on the flight, but the plane probably was at least a quarter empty.

The two agents at the gate were busy nonstop trying to rebook connections for travelers. It was clear that neither had time, for example, to make a call to another gate or the United Club alerting them to the empty seats. (No one was on the waitlist because the flight was past departure time and the reservation system isn’t set up to deal with that situation.)

Earlier this year, I was able to get a family of five onto a flight from Denver that United told them was full. Yes, again, it went out with empty seats at the same time the airline was telling people they would have to spend the night at an airport hotel.

Similarly, after the Asiana crash at San Francisco Saturday, and most flights canceled for the rest of the day, flights in and out of SFO showed full until Wednesday. Again, I heard stories from passengers who stood by and got on flights with empty seats, while others were sleeping in the airport. (It wasn’t just at SFO — one client made it home from Chicago, despite the system saying nothing was available.)

Now, does this always happen? No. But, when things get chaotic, often the reservation system is overloaded. With only online check-in, it’s often very hard to know how many people are really there at the airport. Some miss connections, some get on other flights without canceling their original bookings, etc. With these and other cases, roving agents could easily go between gates, or for that matter, customer service agents could call gates to check on flight loads.

I’m not talking about trying to fill the very last seat on every flight, though no doubt airlines would like that for the revenue and potentially stranded passengers would like to get to their destinations. But, it seems like it wouldn’t take much of an investment to have a handful of employees whose job it would be to directly monitor gate situations and direct traffic accordingly.

For that matter, on days when flights are canceled or delayed, more humans working customer service means more people actually getting on planes, instead of standing in line. That translates, again, into fewer empty seats. My sister recently had a situation where I used a special travel agent phone number to reach a reservationist during a Charlotte weather delay. She was able to get a boarding pass at the gate and made it to Los Angeles on a plane that wasn’t full, while the customer service line snaked around the airport.

It’s not just passengers who lose out when customer service is turned over to machines. When planes go out with empty seats, that’s lost revenue for the airline and potentially more lost revenue if they have to turn away other paying passengers on later flights.

Yes, paying human beings costs money, but not paying them may end up costing airlines more.