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
Last year, stocks hit the wall in the spring. Will 2013 be a replay?
Advisers are more bullish on the markets than their rich clients, which may also be pointing to a disconnect in risk tolerance.
Signs that markets are becoming less macro-driven as correlations fall.
April has been a struggle for the UK, with the country’s PMI Composite Index falling from 51.5 in the preceding month to 48.2. But even with dour consumer sentiment and a softening job market, UK growth could surprise to the upside.