Over and over we read something like this, “If it’s a really complicated and/or special trip, you should consider using a travel agent, but for simple flights within the U.S, just go ahead and book online.”

And yes, online booking for domestic flights is easy — until it isn’t. And, until you’re actually flying during a time with full flights or bad weather. Or, both.

In the same way that many travelers book online, airlines are trying to computerize whatever they can. One airline focus is the rebooking process in case of problems. This makes sense from the airlines’ profit perspective; less sense, if you’re a stranded traveler.

Here are a couple examples. In the first case, a young friend on a budget had booked through Orbitz, which in theory is a travel agency, albeit an online one.

She had booked a United flight roundtrip from Milwaukee to San Francisco, but got a message two days in advance that her redeye San Francisco flight to Chicago had been canceled. She tried to call United and couldn’t get through. So, she apologetically messaged me on Facebook. Had we booked the flight, it would have been easy to change her to a flight only an hour earlier. But agents can’t change another agency’s booking, or a booking made direct. So, I suggested she call Orbitz.

That apparently took 45 minutes and the Orbitz agent insisted the flight hadn’t been canceled, because it didn’t show canceled in her system. (Some reservations systems really limit what agents can do/see, though hard to know if that was the case or if the call-center agent was just incompetent.) Orbitz suggested she call United and offered her the same 800 number that was impossible to get answered.

In the meantime, we both also tried on, but the site was unable to help, giving the error message “please call United.” Yeah, right,

At this point I called a special number I know for agents, only waited about 15 minutes and found a competent person at United. I apologized that it wasn’t my booking, but explained that this young woman was having a really bad time. The United agent made the relatively easy switch.

In another case, a client was going to a big meeting in Florida, with an expensive pre-booked hotel. This client had a nonstop flight on American from La Guardia.

One problem: fog in the New York area cancelled her flight, and American sent her a message to go to JFK, where they had rebooked her on a connecting flight via Baltimore to arrive about 8:30 p.m. When she got to JFK she then discovered that the connecting flight to Baltimore was scheduled to land AFTER the connecting flight from Baltimore left.

At the American counter they apologized for the computer error, but said they couldn’t do anything at all until the next day. She also checked on her smartphone; indeed, all the American flights were sold out.

At this point her dad got involved and called me. As reported, flights to Miami were full. But Miami also is near a number of other airports. It didn’t take too much searching to find JetBlue flights to Fort Lauderdale, which is only about 25 miles from Miami. I snagged her the last two seats on a flight leaving in a couple hours.

At this point American agreed to refund the original outbound ticket, or curiously, to book her on an evening JetBlue flight, now that we had the Fort Lauderdale idea. But, since the new JetBlue was only about $100 more than the first ticket, she just had me issue new tickets. She and her boyfriend made it to the meeting, and were on time for dinner.

Was this rocket science? No. Presumably someone with a laptop, tablet or smartphone might have been able to find these flights, too, assuming they knew how close Fort Lauderdale is to Miami and assuming they had power, and a good connection, etc.

Fortunately, most domestic trips don’t turn into the kind of nightmare travel we’ve seen this winter. And yes, when a trip goes smoothly, or a canceled flight is either automatically changed to something reasonable, or easy to rebook, then it is easy to think, “Why pay a travel agent?” But, considering the amount of time and money many people invest in travel, when things really go bad, having access to an good old-fashioned human may feel like the best bargain of all.