If you haven't heard of Scott's Cheap Flights, it's a website that provides “the world's best flight deals. Handpicked by experts.” and allows you to “get email alerts when our experts find cheap international flights departing from your favorite airports.” Scott himself was on the internet providing tips and tricks.
Cheaper oil = cheaper fares. Airline CEOs spent much of the first half of 2018 predicting (wishing?) that airfare will get more expensive, pointing to the rising price of oil. But with the price of oil down 40% in last 3 months of 2018, one of the main drivers of expensive flights is off the table.
Worldwide economic slowdown is bad in general but probably good for airfare. Many economists are predicting slower economic growth in 2019 and 2020. When times are tight, discretionary spending like vacations are one of the first items on a family's budget chopping block. Lower demand for plane seats will force the airlines to cut fares in an attempt to woo those travelers back.
Hawaii flights are going to get even cheaper. Southwest is set to imminently begin flying from the mainland US to Hawaii (and between Hawaiian islands). Other airlines like Alaska, United, and American have already been dropping their fares in anticipation, but I expect that trend to continue even more in 2019. Plus with free checked bags and free changes/cancellations, many flyers will find Southwest's Hawaii flights especially valuable.
Mistake fares will continue. Mistake fares are when an airline or online travel agency like Expedia or Orbitz accidentally offers fares that are significantly lower than normal. For instance, the $130 nonstop roundtrip flight from NYC to Milan that jumpstarted my career in cheap flights. Though not common, they show no signs of abating and should give flyers more opportunities at rare deals in 2019.
From there, he went on to provide specifics about what's coming up, how to keep on top of deals and things like:
Are you familiar with the 24-hour rule? It's one of the absolute best perks for travelers but many folks aren't aware. When you book directly with the airline, federal regulation requires the airlines to give you a 24-hour grace period afterward during which you can cancel your ticket without penalty.
…they're not required by law within 7 days. But each airline's policy differs a bit as to how they handle it.