Airlines in America: have smaller ULCCs cracked the code?

Now that Spirit Airlines appears to have rebuffed Frontier Airlines' overtures once and for all, the ultra-low cost landscape in the US is showing more clarity - at least, in the short term.

Two of the country's more niche ultra-low cost airlines - Sun Country and Allegiant Air - appear to have favourable prospects for this year as US market conditions remain benign, and each airline executes on its respective strategies.

Neither Sun Country's, nor Allegiant's, model lends itself to consolidation, and each airline believes that M&A is not necessary for those companies to thrive in the market.