Examine the impact of Covid-19 on a particular sector of the travel industry, using advanced microeconomic theory (for example analysing the sector with the use of Edgeworth Boxes, or utility functions (etc.), or other relevant models, such as Bertrand competition etc.)

As I seem to be stuck with the generality of the question could you please provide examples of theory application in this sector? For example, examining the airline industry in terms of Bertrand competition.

Thanks in advance.