Airplane food tends to be more of a punchline than a pleasure. And yet, at 35,000 feet, even a forlorn-looking tray can serve as both entertainment and sustenance for a captive audience. With that in mind, Charles Platkin, PhD, director of the New York City Food Policy Center at Hunter College, sought to uncover just how healthy or unhealthy airplane food is, and the results are published in the Annual Airline Food Investigation, a survey he's conducted since 2000 (it became annual in 2009).

For the survey, Platkin reached out to representatives with 12 major airlines to inquire about their meal and snack options. He ranks them based, in part, on calories, nutrition, menu innovation and transparency (some airlines are more candid than others about what's in their food).

"They call me an airline food bully," says Platkin, who is also founder of the site DietDetective.com. "I'm aggressive about it. People have choices about what airline they fly, but they don't have choices about what they eat on that flight," he says.

Each airline is given a "health score" on a scale of 1 to 5, with 5 being the highest. This year, Delta and Virgin America tied for the lead, with each scoring 4 points, and Air Canada tied for second with JetBlue. Hawaiian Airlines came in last.

It's telling that no airline scored the highest rating of 5. "The airlines still have a tremendous amount of room for improvement," says Platkin. "No airline blows me away, like, 'Oh my gosh, they got it.' " To that end, he was more inclined during our interview to use phrases such as "not awful" when describing a meal or snack, rather than showering it with praise. While a handful of those surveyed serve complimentary meals on select flights (Delta, American and Hawaiian), Platkin is more inclined to encourage health-conscious passengers to eat a full meal before they fly and to carry their own snacks (nuts, fruit, vegetables, hummus) onboard.

Here's how the 12 airlines scored, along with some of the "Best bets" to munch on from each. (For the full survey and more "best bets" and nutritional info dietdetective.com/annual-airline-food-investigation-2017-18).

Delta

Cooperation in providing nutritional information: Excellent

Health score: 4 stars

Average calories overall (meals, snack boxes and individual snacks): 480

Delta was notable for its willingness to share nutritional information, its variety of offerings and the fact that the average calories in the snack boxes, meals and individual snacks decreased from 2016's 527 to 480, and meal calories decreasing from 628 calories to 559. Delta has also begun offering complimentary meals in economy class on select flights.

Best bets: For a snack, opt for the almonds (124 calories); the vegan, GMO-free Delta Flight Fuel Tapas Snack Box (it should be eaten as a meal, not a snack, because of the higher calories, says Platkin), which has Super Seed Crackers, Snapea Crisps, almonds, hummus, quinoa with pepper dip and other items (665 calories); the fruit-and-yogurt continental breakfast (345 calories if you save the Kind bar for later); the sesame noodle salad (345 calories); or the Greek mezze plate (330 calories).

Virgin America

Cooperation in providing nutritional information: Excellent

Health score: 4 stars

Average calories overall: 340

Platkin says that healthier options and openness about calories and nutrients have all been a part of Virgin's approach since the airline launched (although it has since been purchased by Alaska Airlines).

Best bets: Go with the nuts as a snack (Creative Snack Brain Smart Nut Mix, 510 calories, and Hail Merry Seasoned Nut Blend, 220 calories) and share them or save part for later; opt for one of the meals, such as the 420-calorie, vegetarian protein-packed quinoa wrap; the 440-calorie protein plate with a cage-free hard-boiled egg, cheese, grilled chicken breast, fresh vegetables, wheat pita rounds and edamame hummus; or the 390-calorie farro salad.

Air Canada

Cooperation in providing nutritional information: Very helpful

Health score: 3.75

Average calories overall: 320

Best bets: Skotidakis fat-free vanilla Greek yogurt (90 calories); Avocado Smash Box with fresh guacamole, aged cheddar cheese, hard-boiled egg, green apple slices, multigrain muesli bread, chili flakes (590 calories).

JetBlue Airways

Cooperation in providing nutritional information: Somewhat helpful

Health score: 3.75

Average calories overall: 337

Best bets: Platkin highlights the Amp Up Box, with hummus, a fruit bar, olives, crackers, almonds and other items (425 calories) for its nutritional value, but acknowledges the calories are high. Other good choices on select flights: yogurt and granola (210 calories), kale and quinoa salad (320 calories).

Alaska Airlines

Cooperation in providing nutritional information: Extremely helpful

Health score 3.5

Average calories overall: 479.6

Best bet: Platkin suggests sharing the Mediterranean Tapas Picnic Pack (vegan, kosher and gluten-free) or having it as a meal, because it's 510 calories. It comes with multigrain snack chips, olives, hummus, almonds and more.

United

Cooperation in providing nutritional information: Somewhat helpful

Health score: 2.75

Average calories overall: 416

Best bet: For a snack, go for the hummus (160 calories) or the Tapas Snack Box, which comes with a variety of items including flatbread, crackers, bruschetta, hummus, almonds, mints and more (avoid the cheese spread, says Platkin). The Mezze Sampler (501 calories), is another good option.

American Airlines

Cooperation in providing nutritional information: Below average

Health score: 2.5

Average calories overall: 446

Best bets: Go for the hummus box as a snack (220 calories) or the Chicken Arugula Wrap (when available) for lunch and go easy on the dressing (401 calories).

Frontier Airlines

Cooperation in providing nutritional information: Very helpful

Health Rating: 2.25

Average calories overall: 372

Best bet: Snack options are fairly limited. Go for the Colorado Nut Co. Trail mix (393 calories).

Southwest Airlines

Cooperation in providing nutritional information: Very helpful

Health Score: 2

Average calories: 125

Best Bet: Southwest offers a fairly limited selection, but the ones it does offer are complimentary. Peanuts (70 calories) are the best bet, says Platkin, even though the pretzels have lower calories.