Carry-on bag items checklist for planes, trains and other transportation
The Essentials - Documents
Passport
Proof of Travel Information and Authorization System (ETIAS) for travel to Europe
Proof of Electronic Travel Authorisation (ETA) for travel to the UK
Customs and Border Patrol may ask you to provide proof of your return or onward flight information from Europe, showing you are not intending a long-term stay.
Customs and Border Patrol may ask you to provide confirmation on where you will be staying.
Customs and Border Patrol may ask you to provide bank statements from the last three to six months, original, stamped, and signed by the bank. (Show you have sufficient funds to cover the length of your stay, typically $100 / day)
Customs and Border Patrol may ask you to provide credit card statements for the last three months, if you don't have a bank account. (Show you have available funds to cover the length of your stay, typically $100 / day)
The Essentials - Basic List
Mobile Phone
Selfie Stick
Camera
Personal Valuables
Charge Cards / Foreign Currency / etc.
Foreign Plug Adaptor - Trains may require an adaptor to be plugged in before you can plug in a USB charging plug
USB Charging Plug - May be required on some trains but most airlines now have a direct USB plug in the seat back
USB Cables - Cables required to plug in your phone and other devices
Reading Glasses / Prescription Glasses
Travel Journal / Pen - Now may be a good time to catch up on any notes you want to write
Travel Pillow
Headphones / Ear Buds - For inflight movies or listening to music on your mobile device
External Battery Backup - Maybe be required for charging your mobile device if no charging ports are available
Hand Sanatizer
Travel Kleenex
Chapstick - It can be dry on long flight, so may come in handy
N95, KN95 or other disposable 3 layer Face Masks - Some locations/countries still require wearing a face mask on public transportation