Dennis Schaal

Imagine if Expedia and Priceline saw selling flights as an increasingly important part of their business and started offering airline IT solutions. That's what they and Trivago are essentially doing on the hotel side of the ledger, embedding themselves as hotel-technology providers. Now it has become a downright trend.

Priceline's and Expedia's respective selling and marketing spend on a global scale shows why Priceline remains on top despite all of Expedia's acquisitions. Priceline does it much more efficiently, getting a lot more bang for a buck.

Priceline's CEO says its "competitive moat is deep and wide." His counterpart at Expedia believes his company needs to get more international. And TripAdvisor's new CFO says it has ample resources for acquisitions. This all should make for an interesting 2016.

There will be multiple winners in flight metasearch and Skyscanner, a relatively smaller player in the scheme of things, has the tech acumen and potential to be one of them. However, the company realizes it will need a merger/acquisition or an IPO to get headed toward where it ultimately wants to go.

Choice Hotels recognizes that traveler behavior is changing. For the sometime-business and other-times-leisure traveler, Choice Privileges members can earn points whether staying in a hotel or in a vacation rental. And because "millennials want instant gratification," according to CEO Stephen Joyce, Choice is giving it to them in the form of perks at check-in.

Expedia's acquisitions versus the Priceline Group's "competitive moat." Rock, paper, scissors. It's an interesting contest and in the $1.4 trillion global travel market, both companies can be winners. Expedia is trending upward and Priceline is showing strong growth, as well.

The argument of Priceline Group CEO Darren Huston is that chains are shooting themselves in the foot -- and their properties aren't happy -- when the chains offer lower rates on their own websites because then their listings on Booking.com won't convert as well as they should. But as Huston says in a different context, perhaps the hotels would reply that they are "playing the long game."

Advertising such as bidding programs can be a higher margin business than transactions for online travel agencies. It looks like Expedia, at least, wants to get involved in that bidding revenue that Google and metasearch players have generated for years.

TripAdvisor believes tours and activities will be its next billion-dollar revenue business and it is upgrading its platform to enable consumers to book tours on the TripAdvisor desktop and apps. It's all about revenue and making TripAdvisor a stickier site to book everything on the planet. Flights anyone?

Expedia's acquisitions in 2015 made it more of a U.S.-focused company, a weakness it intends to rectify in coming years. Meanwhile, the market share impact of its buying spree won't really be felt until 2016 and beyond.