From 5W Infographics, a breakdown of how the bargain basement carriers do it:

AUTHOR
Mick Weinstein
Mick is the Head of Editorial for Covestor, a financial journalist and online content specialist. Prior to joining Covestor, Mick was for five years the Editor in Chief and VP Content at stock market analysis website Seeking Alpha, where he built the editorial function as the site attracted over 3.5 million unique monthly visitors and developed an innovative platform for intelligent stock market discussion. Mick is a graduate of the University of Michigan, Ann Arbor.
380 posts You may also like
Why corporate pricing power may be waning
Why one analyst is bullish on Europe and the euro in 2021
Governor Christopher Waller’s reminder this morning that he’d prefer a rate cut this month coincides with the White House looking for Fed Chair Powell’s replacement. And investors are taking it well.
Why did housing prices rise so much?