There are over 5,000 airlines in the world. I’m not going to list each and every one here, but you get the idea that the airline market is huge globally. There is the international market which serves people travelling from one country to another and there is the domestic market which serves air travel within a country. While you can easily search out airfare yourself for a particular trip from point A to B, its better to contact a travel advisor when you are looking to book a whole package that would include hotels & sightseeing & car rental and/or train. That's because a travel advisor can often times get a special add-on fare. Most travel advisors will not want to book air by itself as there is generally no commission in it since commission deregulation in the 1990's.
As for times when you are travelling on what is called a long-haul flight (flights over 2200 miles) you never know when you might end up on a longer layover than expected and need somewhere comfortable to stay for several hours without having to check into a hotel. Many credit card companies offer a partnership with airport lounges. You can find out more information here with OneWorld and StarAlliance airline loyalty programs.
Here are some airport lounge companies: Priority Pass and LoungeBuddy
Traveling by train has its own advantages in that you don’t have to worry about pressurization in the cabin, like on a flight, and so might be a good alternative for those with inner ear issues.
It may also take longer to get to a destination, however the scenery to view out the window along the way makes for a relaxing way to travel.
Cross-country trips are available on Amtrak to see the USA, ViaRail to see Canada, the Trans-Siberian Express to see Russia and Mongolia. Other countries have train systems that are a great way to get around an unfamiliar country especially if you don’t want to rent a car and drive, and yet, you want your independence to go on your own schedule rather than pre-set touring on a bus.
Eurostar is a high-speed railway service connecting London with Amsterdam, Avignon, Brussels, Lille, Lyon, Marseille, Paris and Rotterdam. All its trains traverse the Channel Tunnel between the United Kingdom and France, owned and operated separately by Getlink.
VISAS It is best to check with a company or official governmental organization for the country you plan to visit. Click on the image link below to help you find all the information you need on obtaining a Travel Visa