Even without a pandemic, holiday travel isn't for the faint of heart.

Millions are expected to travel this month, with threats of volatile weather and the omicron variant further stressing out people eager to close Year 2 of the pandemic.

To help travelers prepare, CNBC Travel asked industry insiders this question: What's your one, solid tip for people traveling this December?  

Tips for travel planning

"Plan for the arc of the trip. Think of a trip like a story with a beginning, middle and end. For example, plan to have the nicest hotels at the end, building up to end on a great note. Then for the entry and exit, plan for ways you can ensure they go smoothly. Maybe it's arranging private transport after a long flight, so you don't have to navigate the public transit system amid jetlag. Whatever a solid arc looks like to you, plan it in advance."
—Sarah Groen, founder of the luxury travel company Bell & Bly Travel Design

"If you're planning to do some Greek island-hopping, keep in mind that Greeks themselves tend to stick to one island instead of cramming as many as they can into a single trip. Think thematically: Santorini has stunning scenery, but beaches are better in Mykonos … [but] islands like Tinos and Syros have great food and culture with significantly lower hotel prices than Mykonos. Crete has lots of variety, but a car is essential."
—Anthony Grant, American writer based in Greece

Tips for flying during the holidays

"Choose early morning flights, which are typically less crowded. Avoid taking the last flight of the day whenever possible, especially during the winter months to reduce the chances of missed connections or delays due to cancellations or weather. … Opt for carry-on luggage on your next trip. You'll skip lines when you arrive at the airport and won't have to wait for luggage when you land."
—Anna Brown, public relations manager at Expedia U.S. 

"Pack a change of clothes in your carry-on. Be prepared for the worst. … With airline shortages and increased travel, there's a higher-than-average chance your luggage will be lost. Don't travel with your gifts. … Consider shipping presents directly to the final address."
—Mark Hoenig, co-founder of digital travel company VIP Traveler 

"Buy your tickets ASAP. As people postpone their international travel plans due to Covid concerns, domestic flights tend to get more crowded and expensive. To expedite security at the airport, do not wrap gifts in case they need to be inspected."
—Rajeev Shrivastava, CEO of travel insurance marketplace VisitorsCoverage.com

Tips for renting holiday homes

"Look for vacation rentals with the most flexible cancellation policies, so you can nix your stay at the last minute for any reason.

"Short-term hospitality brands are on major booking channels but also have their own direct booking websites. Booking stays directly with the brand usually comes with a discounted rate. And, many of these … provide co-working spaces and digital concierge services. … Examples of such brands include Casita, D Alexander and Sentral."
—Vered Schwarz, COO of vacation home rental software firm Guesty

Tips for family gatherings

For pre-Christmas travel: "I suggest traveling within your family and friend 'travel pod' made up of those people who you will be spending the holidays. Should you need to quarantine once you arrive home for any reason, you will already be with the family members or friends you plan to spend the holidays with."
—Matt Berna, managing director of North America for travel company Intrepid Travel

"Ventilation remains really important. That's one thing I think remains to be overlooked and underappreciated. With holiday gatherings coming up, I certainly plan, no matter how cold it is outside, I'm going to have my windows cracked by four to six inches… [and] testing immediately before gathering, ideally the hour or two before, maybe the morning of, is what we ought to be doing."
—Stephen Kissler, research fellow at Harvard T. H. Chan School of Public Health, in an online discussion on Dec. 9 with Elana Gordon of "The World" public radio program

Tips for booking hotels

"A lot of the best hotels block online reservations for the peak 'festive' season… and manage it directly via their human team. It's worth asking your travel advisor for help as they often have the relationships to accomplish the impossible when everything seems to be sold out."
— Henley Vazquez, co-founder of travel company Fora

"Independent boutique hotels and locally owned businesses need love more than ever, being that they don't have the privilege of extensive conglomerate funding to stay afloat. So, with this in mind and in the holiday spirit, give back to the destination you're visiting by revolving your vacation around staying at these types of places and supporting local operators."
—Brandon Berkson, founder of travel company Hotels Above Par

Tips for traveling with young kids

"Plan some downtime for your babies and toddlers during your holiday travels… children don't always do well when they are constantly on the go. Make sure to schedule some time each day to just sit, relax, play with toys and engage with your kiddos.

"Kids need frequent breaks from people and planned activities to let their minds run wild with creative play. Make sure to pack enough toys to keep children busy when you are preparing meals, engaging in adult conversation or for when they just need a reprieve."
—Fran Maier, CEO of baby equipment rental company BabyQuip

Tips for renting a car

"Many car rental companies offer contactless pick up where you can just walk onto the lot and hop in your car. On Expedia, use the "Skip the counter" filter to find these options and avoid waiting in yet another line."
—Anna Brown, public relations manager at Expedia U.S. 

"When reserving a rental car, book a 'pay later' rate… which gives you the flexibility to cancel and re-book if a better deal comes along. Rental rates can change multiple times per day. AutoSlash games the system by continually checking prices for your rental, and they let you know if they find a lower price."
—Jonathan Weinberg, CEO of rental car price tracking company AutoSlash