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.