Travelling by plane - advices

Hello everybody!

In a few weeks I will be flying from Zagreb, Croatia to Lisabon, Portugal on a 5 day vacation trip. Since it will be the first time to fly with me photo gear I wanted to ask you what are your advices on that subject.

All my photo gear can fit into Lowepro Mini Trekker AW which I plan to take on board. Do you know if that is acceptable with airline companies? Also, what should I do with my tripod (how can I transport it since I don't have any special bag for it) and should I register my gears on the customs before leaving the country and if so, what is the procedure for that and how early should I arrive?

If you think something else is important, please share it as well.

Thank you in advance!

Regards,
Tom