Would the person taking the action in question be willing to have everyone act that way? Is the person taking the action treating others with respect?

Is the person taking the action treating others in ways that they have consented to be treated? (Carroll, 2000; Velazquez, 2005).

Analysis-

SW, and most of the major airlines, have not reacted with fairness with their seat sizes; Americans are growing larger, but seat distance and sizing remains equal to, or smaller, than 3-4 decades ago. This is unfair and unethical because it punishes everyone, not just the obese.

Airlines regularly charge for excess baggage based on their own rules; excess girth or weight is not so different. Tickets are based on clients comfortably and safely filling a seat- if either issue is off, then the process becomes unfair.

It is not just the obese passenger's considerations that must be addressed, but the other passengers who also paid for a seat. Allowing an extremely obese person to "squeeze" into a seat would further discomfort the other passengers in the aisle, and even cause safety and accessibility issues.

There is a tremendous amount of greyness in some decisions flight attendants must make; people and luggage are both shaped differently, hardly universal, so issues must be put into context for the larger...

Ultimately, the flight attendants and cabin crew are responsible for the safety of the entire passenger list -- and they must base their decisions on what is, or might be, the best for all concerned.
Certainly, to make the situation fairer the policy must have dual tabs: height v weight in a given situation. This allows for procedural fairness; distributive fairness over time, and that despite the potential embarrassment to the overweight passenger, the safest and fairest outcome would be to adhere to the rules about purchasing two seats under identified criteria.

REFERENCES

Carroll, A. (2000). "Ethnical Challenges For Businesses in the New Millennium:

Corporate Social Responsibility and Models of Management Morality."

Business Ethics Quarterly, 10, 1: 33-42.

Leventhal, G., et.al. (1980). Beyond Fairness: A Theory of Allocation Preferences. In Mikula, G., ed. Justice and Historical Interaction. New York: Plenum Press, pp. 167-218.

Velazquez, M. (2005). Business Ethics: Concepts and Cases. New York: Prentice Hall.