There are a lot of rules what passengers cannot do inside a plane, what can they carry into their bags or luggage, and even when can they go to a toilet. There is an infinite list of cases when passengers tried to foolish airport stuff and take some illegal things to the cabin. Also, there is another infinite list of some illogical rules made by particular airlines. As a result, it is always recommended to check the website of the airlines before your flight and look after any specific rules or requirements to avoid some additional expenses. However, there are some general and international requirements of aviation safety that every passenger must know.
It is not important how many times you have been on a plane before, pay attention to the flight attendant safety briefing at the beginning of your flight, read the safety card, and memorize where is the nearest exit you might use in a case of emergency. It is recommended to wear your seat belt all times while seated because it can help to avoid even small injuries in case of unexpected turbulence. Also, do not forget to use the special seat and belt for your babies and toddlers.
Mostly, there is a standard size and weight of cabin baggage and it is the same for many airlines. However, there can be some variations especially if you are using cheap airlines. Usually, the allowed weight of a cabin bag is from 7kg up to 10kg, so make sure your bag is not too heavy and it will not be needed to pay extra fees. Do not take any restricted or prohibited items such as knives, guns, scissors, explosive material, or liquids in bottles that are exceeding 100ml. Pack all your shower stuff in small containers up to 100ml and put them in one plastic bag that is not exceeding the overall limit of 1l.
While being at the airport, do not forget to take your cabin bag always with you. It is absolutely prohibited to leave unattended baggage in the airport terminal. Carefully listen to the instructions of flight attendants where to put your bag because sometimes it should be put under your seat and sometimes you might leave it in the overhead compartment. In case of emergency, you must leave your bags and take care of yourself first.
Inside a Cabin
The first and most important rule is to act adequately and listen to the instruction of flight attendants. Do not make any circumstances that could be harmful to you, other passengers, or cabin crew, otherwise, you will be taken out of a cabin by police and will get a huge fine. Do not forget that there are less oxygen and different pressure inside a cabin, as a result, drink some water regularly, limit the consumption of alcohol, coffee, strong tea, or any other caffeinated drinks. Take extra care of your safety if you have some heart, blood, or lung disease. In case some extra oxygen would be needed personally to, you must inform a cabin crew before your flight.