Rental car companies use a variety of labels to indicate the size of their cars. Each company uses different car brands and types, so you need to ensure you know what type of car you are obtaining. A compact car at one agency might be midsize at another. Many rental companies also offer customer loyalty or membership cards that provide free upgrades to members. Obtain one in advance or look for Internet specials when booking.

Compact Car Meaning, the Small Cars

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Sub-compact, compact, economy or small are the standard labels used for cars at this end of the spectrum. Compact cars are usually suitable for four to five people and a couple of suitcases, have two or four doors and are likely to be automatic transmission. The smallest compact cars – models such as the Chevy Aveo, Kia Rio, Ford Focus and Hyundai Accent – are the cheapest to rent and have great gas mileage.

Currently, we find the Nissan Versa and Ford Focus available for rental around Los Angeles Airport. Some companies list compact cars as Small Sedans, which having driven a Ford Focus, is a misnomer. Bottom line, in a parking necessary city, you want a small car to find good spaces.

I cannot tell you my frustration getting a "free upgrade" to a Ford F-150 and paying for Gas. If you want to save money, rent a compact car.

Midsize Cars

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The next biggest category is known as intermediate, standard or midsize. At Dollar, this size includes cars such as the Ford Fusion and Dodge Avenger. Five people can fit a little more comfortably than in the smaller classes, and there is room for more luggage, but gas mileage decreases as the car gets bigger.

Full-Size Vehicles

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Next to an SUV or van, full-size cars have the most storage room and passenger capacity. At Enterprise, the Chevy Impala, Nissan Altima and Dodge Charger are the featured full-size vehicles and are four-door sedans with lots of features, including air conditioning, power locks and windows, an AM/FM stereo and a CD player.

Premium/Luxury/Specialty Cars

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If you desire a convertible for your California or Florida road trip, have a wedding function to attend or need to impress a business colleague, this category meets the needs of those with the ability to travel in style and comfort.

Try a Ford Crown Victoria, Lincoln Towncar or a BMW, perhaps the 528. Avis' specialty lines include the Ford Mustang Coupe, Mini Cooper and Volvo C70 convertible. Space and passenger capacity varies greatly, as does gas mileage.

SUVs, Vans and Pickups

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When you need to haul equipment, travel over rough roads or need more passenger space, most rental companies have a wide selection of pickups, vans (including passenger and cargo) and SUVs, both regular and luxury. While they hold more people and luggage, these vehicles get very poor gas mileage compared with smaller cars.

Potential models include the GMC Yukon, Jeep Wrangler, Dodge Grand Caravan and Ford F-150.

Hybrid and Electric

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Many car rental companies now offer environmentally friendly hybrid or electric cars featuring great gas mileage and a low carbon footprint.

Hertz has a Green Traveler collection, meaning all cars get a minimum of 33 miles per gallon; this line includes the Jetta TDI Clean Diesel, Honda Compressed Natural Gas Car, Hybrid Sedan and Nissan Leaf EV.

At the LAX Hertz, they offer the Tesla Model Y and Tesla Model 3. If you do rent an electric vehicle, ensure you know the availability of electric hook-ups.