Carry on Luggagge
There are several different versions of Carry on...

There are several alternativs for luggage when traveling. When we think of airtravel, it is usually diveded in two categories: Check in and carry on. The latter can be more varied than you think
Personal Item
This is generally included in the ticket. The measurements can be 40 cm x 30 cm x 15 cm. This can be something like a tote-bag or a backpack. YOU MUST CHECK MEASUREMENT AND WEIGHT WITH YOUR AIRLINE!
Carry on suitcase
This is the most popular item to bring into the aircraft. It is usually a suitcase, a so called "spinner" on four wheels. The measurements vary among airlines. Quite often it is with the measurements 55 cm x 40 cm x 25 cm. YOU MUST CHECK MEASUREMENT AND WEIGHT WITH YOUR AIRLINE!
Under Seat
This is a category that some airlines use. Those who do are extremely strict on the measurements. They will make you put your luggage into a rigid form to test. Please note that wheels and handles must also fit.