Transportation
Transportation is a broad subject encompassing a vast number of companies and operators, only a few of which I will be able to mention here. When it comes to airfare, everyone has their favorite search websites and there are plenty to choose from. Once it comes down to making an actual purchase, I generally prefer to book directly with the carrier unless the price is significantly less (which is rare). The airlines like to take care of their own and should a problem arise, you want them on your side. I have found that if your itinerary is more complicated than a simple roundtrip, it can often pay off to speak to a human. Call me old fashioned, but it works.
A frequently underutilized tool when it comes to the small “moving parts” of a trip is your hotel concierge. Besides making dinner reservations and securing event tickets, they are an excellent source of knowledge and ability when it comes to transfers, train tickets, etc.