I flew 21 hours with my 4-year-old. Here are the 9 things I packed in my carry-on that helped us make it through the trip.

I've been lucky enough to travel with my 4-year-old son to many places, and in October, we embarked on our longest haul yet from New York to Zambia.

My husband, son, and I flew took a total of four flights across four continents in the span of two days.

As you can imagine, I needed a thing or two on these long-haul flights to make the trip a little easier. Here's what I packed in my carry-on.

For this 10-day getaway, we put most of our belongings in our checked luggage, but I needed a smaller carry-on for the essentials I needed in the air.

Those onboard items were critical, as they had to hold us over for two days of travel. So, I needed a bag that was big enough to carry everything but wasn't cumbersome.

I opted for the large nylon and leather backpack from PAK Rêve, a premium family-travel brand I'm launching in 2023.

The bag is 14 inches wide, 12 inches high, and 8 inches deep. It has two large water-bottle holders, interior and exterior pockets, and attachable accessories. I used every single feature.

When traveling as a family, it's necessary to keep all essential documents, like passports and coronavirus vaccine cards, in one place. Therefore, I don't trust anything but a zip-close passport holder.

The one we use is from Eagle Creek and has enough room for all three of our passports, Global Entry cards, vaccine cards, airline tickets, and a pen for filling out documents.

It even has a little handle that makes it easy to carry through customs.

I tend to get dehydrated when I travel, so I always bring a refillable water bottle.

Usually, I tote around my large Hydro Flask. But since we were headed on safari, I opted for a LifeStraw water bottle this time. It has a built-in filter that removes potentially dangerous bacteria and parasites from water sources.

I also had my son's regular water bottle in the other large side pocket. We regularly filled it during the plane ride to keep him hydrated.

My 4-year-old would've loved it if we packed up every truck and train from home, but space was limited so I prioritized things that would keep him the busiest for the longest. A mini sketchpad did just that.

The brand Melissa & Doug has compact sketchpads in a spiral notebook, making it easy to fold the pad in half, with perforated edges on the paper.

My son could color, play tic-tac-toe, or rip the paper out to make paper airplanes and other objects. We also used the pad and crayons to start an alphabetical list of the animals we saw on safari.

It was the most useful entertainment item — besides an iPad and some LEGOs — that my son kept in his Companion PAK, a mini version of my nylon backpack that attaches to the bigger version.

Although I can get as hangry as my son, I won't have a complete meltdown like he will.

That's the reason bringing snacks was key, especially since in-flight meals weren't necessarily served on a toddler's schedule.

But long-haul travel can mess with digestion, so I couldn't just fill him with animal crackers for 21 hours straight. Instead, I filled my bag's attachable insulated pouch with high-protein and fiber food pouches, nutrient-dense bars, beans, and fruit.

It was an ideal way to keep him full and nourished and start our trip in a healthy way.

One of my travel-related pet peeves is the wide variety of audio jacks. Sometimes my phone, my iPad, and the airplane all have different ones.

No matter where I fly, I bring multiple sets of headphones. On this trip, I kept my larger noise-canceling headphones at home to save space.

Instead, I brought in-ear Bluetooth wireless headphones for my phone, in-ear wired headphones with a flat jack, and ones with a traditional round jack. Plus, I had a special smaller pair of over-ear headphones for my son.

I wanted to ensure that no matter which device my son or I used, we had a pair of headphones that worked.

Of course, I also brought two device chargers to keep everything juiced up.

One of my top travel tips is to keep essential medicine in your carry-on in case your checked luggage gets lost.

We were on an antimalarial regimen for this trip and needed to take our medicine while traveling to stay protected for our safari.

I also wanted to have over-the-counter medicines on hand to reduce the aches and pains of traveling.

So, I brought adult and children's Tylenol in case of a fever, children's Zyrtec for any potential allergies, and kids' melatonin to help the whole family survive jet lag.

I kept all of the medications in a Ziploc bag for easy access, checked everything else, and knew that if we needed something in transit, we could go to an airport pharmacy.

However, travelers should always consult their doctor before taking a medication for the first time, especially when they're traveling.

After experiencing a flight delay on a previous trip, I learned my lesson about packing multiple diapers and backup clothes in my carry-on.

Otherwise, it's a mess.

This trip was two days of travel with numerous naps and sleeps. To be safe, I packed five Pull-Ups, two backup outfits, and a packet of wipes that came in handy for cleaning surfaces and faces.

I placed everything in my waterproof wristlet, so it was easy to grab and go in case of an emergency.

I didn't need a coat since we were traveling to a warm destination, but airplane and airport temperatures vary so much that I packed another layer to be safe.

I opted for an oversized, button-up knit sweater from Gsus Sindustries, a Dutch brand, since it was soft, warm, and lightweight.

It was perfect for those chillier travel moments, but it also acted as an ad-hoc pillow or blanket for my son as he napped in his stroller in the airport terminal.

When we weren't using the sweater, I strung it through the front sleeve of my backpack to keep my hands free.