In-flight wireless Internet connections are almost universally available. They’re also almost universally unreliable, slow and expensive.

Just ask Priscilla York, who tries, but often fails, to connect when she travels. On one recent flight, the wireless connection was severed for 20 minutes with no explanation and no apology. But the latest indignity really fried her circuits: She paid $48 for a domestic pass on Gogo. It worked on the flight from Raleigh, North Carolina, to Houston. But then she tried to log in on the flight from Houston to Honolulu, the second leg of her domestic flight.

“To my surprise, it didn’t work,” says York, an author based in New Bern, North Carolina. “I asked the flight attendant if there happened to be a problem on my end, and she said it didn’t work because this was considered an international flight.”

In an always-on society, being disconnected even for a few hours is considered unacceptable – including when we’re six miles above the Earth. Airlines know that, but they also see an opportunity to collect a little extra money, even if it means resorting to a little geopolitical revisionism. (Last time I checked, Hawaii was still part of the country.) Too often, the result is the worst of both worlds: a pricey, sluggish connection that fades in and out.

Steve Nolan, a spokesman for Gogo, which has partnerships with 12 commercial airlines and is installed on more than 2,500 commercial aircraft, said his company’s cellular-based technologies work only over land. But, he said, improvements are on the way for Gogo customers.

Gogo’s next version will bring 20 times the bandwidth of its first-generation technology, he said. “This will basically allow passengers to do anything they are used to on the ground, including stream movies.”

There’s an almost 8 in 10 chance that you’ll have the option of a WiFi connection on your next domestic flight, according to a recent survey by Routehappy, a company that evaluates the quality of your in-flight experience. But the study doesn’t say whether it’s a good connection. That’s harder to determine, and it’s relative. If you compare it with the average home broadband connection, it’s downright awful. When you compare it with the average cellular connection, it’s not so bad. Fortunately, when things go wrong, airlines often will cough up a quick refund.

Routehappy measured connectivity based on a metric called available seat miles, an airline term for a plane’s passenger capacity. It’s equal to the number of seats available multiplied by the number of miles flown. By that measure, the three legacy carriers came out on top. The No. 1 carrier, Delta Air Lines, offers more than 500 million available seat miles with in-flight WiFi, followed by United Airlines (also 500 million miles) and American (more than 400 million miles).

“That’s a fair way of saying which airlines have WiFi and which ones don’t,” says Jason Rabinowitz, Routehappy’s data research manager. But it’s not the only way. Some smaller airlines, notably Virgin America and Icelandair, have more planes with WiFi – both are high in the 90th percentile. And Scoot, a low-cost, long-haul airline based in Singapore, offers wireless coverage in all of its aircraft.

Most important, there’s the quality of the connection, which is difficult to measure. Rabinowitz said only a handful of aircraft, most of them operated by JetBlue Airways, offer wireless connection speeds fast enough to stream a Netflix movie or a Google Hangout. Virgin America and some United Airlines planes do, too, but these three airlines are the exception rather than the rule.

Connection speeds are only half the problem. Often, the signal isn’t available at all, which explains why York’s pass worked only on the first leg of her flight, which originated in Raleigh.

“The automatic in-flight announcement will tell passengers that we have all this great WiFi and they can stream their favorite programs,” says Tim Kirkwood, a veteran flight attendant and author. But his airline uses land-based technology to connect to the aircraft’s wireless systems, and on the routes he flies to the Caribbean, that means the plane quickly goes out of range. “So by the time we reach the 10,000 feet minimum for WiFi to work, we’re offshore and the WiFi doesn’t work.”

Even the best airlines have bad moments, passengers say. “The WiFi on Delta seems to do fine for simply downloading emails,” says Ronald Schmedly, director of a Cincinnati-based nonprofit group. “But for anything beyond that, it struggles mightily.”

He has tried to stream video on his Delta flights, but, he says, “it’s next to impossible.”

“You would like to think that if you are paying $16 for a WiFi one-day pass that the service would be good enough to use however you see fit,” he said. “Unfortunately, it doesn’t seem like we are there yet in 2016.”

Travelers also gripe about the high prices that go along with the languid connection speeds. Connecting to a so-so wireless network used to cost $6 to $8 per flight, recalls Jack Shannon, an Internet entrepreneur based in Venice, California. “Now I often see $30 for an entire flight or $15 per hour on some flights.”

The connection speed, meanwhile, is about the same as before. “They know they have you trapped up there, and they take advantage of it,” he says.

Fortunately, airlines and the wireless companies serving them seem to know that their WiFi is a work in progress, if not also a costly gamble that doesn’t always pay off, and they are usually quick to refund a purchase. Joe Palko, a business-development manager for a Web developer in Chicago, said he gets frustrated by the intermittent onboard connections when he uses Gogo on American Airlines.

“One thing I’ve learned is that when you have an outage, notifying Gogo after you re-connect helps a lot,” he says. “They often will give you credit for the poor connectivity.”

Nolan, the Gogo spokesman, says agents are tuned into requests such as Palko’s. “Our goal is to support all passengers who are having issues with the service, whether that’s in-flight or on the ground,” he says.

Still, prices will probably continue to rise as demand increases, while connection speeds struggle to keep pace. All of which means you can try the WiFi on your next flight, but even on the most wired aircraft, no one will offer you any promises. Only, maybe, a quick refund if the signal goes on the blink.

Special To The Washington Post · Christopher Elliott