Dress exactly as you would to be outside the day that you fly. The air is always a bit cooler up at flying altitude so if it's a warm day then it will be more comfortable up high. If you're flying on a cooler day then bring a jacket just in case.
There are heaters in the airplanes, but everyone's temperature preference is a little bit different so bring long sleeves if you tend to be cold. Closed toe shoes are recommended.
You will be fine. at size 24 your bottom will fit in the seat BUT you may need a seatbelt extender (ask stewards as they pass) and you may find the table in front doesn't come down full.
You are allowed to bring a quart-sized bag of liquids, aerosols, gels, creams and pastes through the checkpoint. These are limited to 3.4 ounces (100 milliliters) or less per item. This is also known as the 3-1-1 liquids rule.
Is toothpaste considered a liquid by the TSA? Yes, toothpaste must adhere to the 3-1-1 rule for liquids and gels. Toothpaste can be brought through TSA security in your carry-on as long as it is 3.4 ounces (100 milliliters) or less and placed in a 1-quart bag.
A standard hold bag is 23kg. You can buy extra weight in 3kgs units, up to a maximum of 32kg per bag. If you're travelling with family or friends on the same flight and booking, you can pool your total weight allowance. No single item can weigh more than 32kg.
While some passengers prefer window seats, aisle seats are often better for overweight passengers that are only purchasing one seat. Window seats are often the better option if you purchase an additional seat.
Strongly consider establishing a formal wind limit to cease seaplane operations. A good rule would be to stop at 15 knots. Above 15 knots, the impact to the aircraft is significant and the passenger experience would likely be negative. If whitecaps are observed, cancelling or delaying the flight should be considered.