At any given airport, the airlines hold long-term leases for passenger loading gates.New gates cannot be added without approval of the airlines.Frequent flier programs are also common in the industry.It is, therefore, more difficult for a new airline to enter a given airport (market) .Such factors: 
Definitions:
Automobile
A road vehicle, typically with four wheels, powered by an internal combustion engine or electric motor, used for transporting passengers.
Trademark
A symbol, word, or phrase legally registered or established by use as representing a company or product, offering protection against its use by others.
Copyright
The protection of the expression of a creative work; that is, protection of the fixed form that expresses the ideas.
Perfection
In legal contexts, often related to finance, perfection refers to the process of securing a legal claim or lien against collateral or assets, ensuring the priority of the creditor's claim in case of debtor's default.
Q29: If a competitive firm's short run average
Q43: The short-run supply curve of a perfectly
Q45: A monopolist's cost curves may shift down
Q49: Differentiate between consumer's surplus and producer's surplus.For
Q67: In Table 10-1 are the short-run cost
Q86: Firms that maximize sales always produce more
Q111: Which of the following is an example
Q149: Price discrimination occurs only in monopolies.
Q150: The differences between a competitive market and
Q167: For a perfectly competitive firm, the long-run