A BETTER FLIGHT

Airlines are also more aggressively selling paid upgrades, although their business model seems to be more varied than that of hotels.

For instance, Alaska Airlines offers paid upgrades within 24 hours of the flight’s departure through Web check-in, airport check-in kiosks, the ticket counter and even at the departure gate. For a one-way flight of 1,250 miles or less, the cost is $50 to upgrade to first class, which increases to $200 for a flight of 3,751 miles or more (with other price points in between). The savings can be $300 to $400 for domestic flights.

Delta’s “same-day standby upgrades” start at $50 for flights of up to 500 miles and increase to $350 for flights longer than 3,000 miles, but you must be traveling on an eligible fare (K or higher) to qualify for a paid upgrade. For a flight from New York to San Francisco, the price difference between an eligible economy class fare and business class is more than $1,500 one way, versus $225 for a same-day standby upgrade, if one is available the day you fly.

United uses “personalized” pricing for its paid upgrades. The offer is based on your frequent flier status, seat availability, itinerary and date of ticket purchase, so different travelers might pay different amounts.

George Hobica, the founder of Airfarewatchdog.com, said he was recently offered the chance to upgrade a $189 one-way United economy fare from New York to Denver for an extra $500.

“Normally that business-class fare would’ve cost $1,800 one way,” Hobica said.

Although he did not buy the upgrade, he said that they are often a good deal.

Jonathan Raiola, an events planner from Brooklyn, said he recently paid $336 to upgrade a United flight from San Francisco to Kennedy Airport, jumping from business to first class.

“For a transcontinental flight, it’s worth it,” he said, especially because the free upgrades airlines sometimes offer elite fliers are “much harder” to get these days.

A FASTER CAR

The car rental industry has a different approach to upgrades, usually offering them at the counter rather than emailing an offer to customers before their trip. For instance, when I reserved a rental car for a visit to Michigan last December, I chose a compact, a decision I debated at the Detroit airport, with a snowstorm on the way. The agent offered a bigger car or an SUV that could better handle icy roads, but I balked at the price: an extra $6 to $9 a day. For an eight-day rental, I figured it would add almost $100 to the final bill with the extra taxes.

Because the compact car kept getting stuck in the snow, I probably made the wrong decision, at least when I made my reservation.

Gil Cygler, president of Allcar Rent-a-Car in Brooklyn, said that upgrades offered at the rental car counter are generally more expensive than booking a bigger car in the first place.

“When you do it at the counter, the agent is getting a commission,” he said. “So you’re usually going to be paying about $8 to $10 more.”

Cygler said the price difference between car classes is typically only a few dollars when you book your reservation, which is what I found when I checked sample airport rentals online. The difference between a compact and an economy car was just $1 or $2 a day, and bumping up from an economy to an intermediate car was an extra $2 to $4 a day.

There are still times when you might get a free upgrade — especially if you’re a frequent renter, you’re traveling at an off-peak time or gas prices are high (and companies have trouble renting bigger, less fuel-efficient cars). Neighborhood dealers might also be more willing to throw local renters a bone.

“Be nice to the person at the counter,” Cygler said. “If I have one reservation today and four cars, something is going to sit. So if I can make you happier, I will.”