4.
Here Pepsico has no obligation, there were contract terms discussed, but the agreement was not finalized as the deal was not yet closed, which means there were still works pending to make it contractually obligatory and enforceable by law.
Though Klien could be at a loss, but there is no contract finalized on which he can ask for damage. So a court has not enforceable contract, hence it can not be forced to sell the plane.
5.
No, if there is a breach it can be contested by law and penalty can be imposed, but by good faith these terms are ignored or let go if a breaching party in one way or other minimizes the loss.
So this is not an obligation but a good faith shown if the party that breaches helps in minimizing the loss of the other party there by reducing the chances of getting into a litigation related to the breach of the contract.
4. PepsiCo entered into a contract to sell its corporate jet to Klein for $4.6 million....