Proof of Onward Travel
This is basically showing at the airline check in counter that you already have a return ticket, or proof that you would be leaving the country. This is mandatory for several countries, without which you cannot get a boarding pass.
Check for Valid Visa
Double check the validity of your passport and that it has at least 2 empty pages if you require a visa at the landing port. Also check for transit visas if required, in order to avoid unnecessary confusion and delay at the airport.
Weighing Your Bag Right
This is a classic travel mistake and makes absolute sense to invest in a luggage weighing scale. Several airlines are very strict about adhering to the exact specified weight of each bag. In order to avoid it, double check the weight of your bag at home or keep a foldable bag handy in which you can transfer the items adding to the extra weight.
Double Check the Flight Time
Even the most veteran of flyers can get confused about their flight times, especially if they are travelling long distances and crossing more than one time zone. Be extra careful at the time of booking your flight and the connections leading up to your final destination.
Losing Track of Time
You might have been optimistic about making it to your connecting flight if your layover time is short, but it is most common to lose track of time at huge airports and eventually having to rush to your terminal. Make sure you have sufficient time to catch a connecting flight, keeping in mind terminal changes/need to collect bags etc.
Not Tagging your Luggage Right
You can tie colorful ribbons or an easily identifiable indication on your bag which can avoid confusion at the baggage collection point. It is also advisable to attach a luggage tag with your name, number and address so that the airline can reach you right away in case your luggage has been lost or left behind.
Miscalculating the Time Required
One might forget to factor in the time that is needed at security checks, customs and passport control and reach late at the airport. One of the most common mistakes is to rush through the counters and make it to the gate in haste.
