Airfare price is the price paid for a route or combination of legs that make up a ticket.
There are various things that affect pricing such as the supply of aircraft, demand from passengers, competitor pricing, even the weather forecast and fleet maintenance schedule can impact published pricing.
In addition, airlines often create price discrimination between its most- and least-flexible fares creating a complex web of pricing for each flight in its schedule. Airlines use complex revenue management systems to revise prices on a daily and often hourly basis.
Currently, data shows that given unpredictable supply and demand, prices are fluctuating more than ever creating an inefficient market for travel. Taxes and fees notwithstanding, net prices for air travel are likely to continue to be less predictable over the next year at least.