=a. To simplify the analysis, assume for now that there is virtually no turnaround time between flights so the next flight can begin as soon as the current flight ends. (If an immediate next flight is not available, the airplane would wait until the next scheduled flight from that city.) Develop a network that displays some of the feasible routings of the flights. (Hint:

Include separate nodes for each half hour between 8:00 AM and 7:30 PM in each city.) Then develop and apply the corresponding spreadsheet model that finds the feasible combination of flights that maximizes the total profit.