Not sure what you should bring with you on the plane? Let me try to give you a quick list of all the essentials you might want to pack into your carry on bag.
Government issued photo identification (usually a state driver’s license or a passport). Not necessarily something you need in your carry on, but something you will need nonetheless. You won’t be able to get through the TSA security checkpoint without it.
An empty water water bottle (you can’t bring liquids over 3.4 ounces but you can bring an empty bottle and fill it up at water stations one you get past security)
A lightweight compact blanket and / or a sweater or jacket. Even in summer airports and airplanes can be very cold places. Most airlines don’t have enough blankets for all passengers and some airlines charge you for them. It is best to come prepared and bring your own.
Medications. Don’t put these in your checked luggage. From time to time checked luggage does get misplaced and it can take days to get returned to you. Don’t put anything in there that you will need. Keep it in your carry on bags.
Car and house keys. Same as above.
Snacks. Everyone wants the free snacks on the plane but there are many reasons why a service might not be performed (turbulence for example). Everything is more expensive in the airport so I suggest bringing protein bars, fruit, chips, and nuts from home. You can even bring non liquid food through the security checkpoint and on board the aircraft.
Earplugs (airplanes can be loud places).
Headphones. Be sure to bring plug in (3.5mm) headphones. Many airlines have in seat entertainment (TVs) with free movies and TV shows. Other airlines have wireless entertainment that streams to your tablet or smart phone. Over ear noise canceling headphones will help you relax and better deal with the crying babies that will surely be seated next to you on your flight.
Computer or tablet. Even if you don’t plan on using it, valuables should be kept out of your checked in luggage.
Chargers. Times are changing quickly and many new airplanes will have both USB and regular outlets at each seat.