.  
closing runways

.  
redirecting traffic flows (in-bound and out-bound from airports)

.  
preferred routing that is temporarily put into place

(3)
Realistic Holding Times (e.g., “Expect Further Clearance”).  With the “tank-limited” flights that one of the major carriers operates, such as DC-9s at the limit of their range, it is important that they receive realistic estimates of airborne delays in order to avoid unnecessary diversions.

In our exposure to the small, niche airline, there were a number of inefficiencies that were unique to the size, scale, and technological sophistication of their operation. For example, the flight crew is completely reliant on voice communication with dispatch and ATC for any information (weather, congested airspace, route optimization calculations, etc.) that would help them replan. Right now, if they had opportunity to choose a different route after becoming airborne, they would not have the tools or information needed to make a choice.
ACARS is a pipe dream for this small carrier. Equipping with any expensive item not mandated is out of the question unless the return-on-investment or increased operating capability is big, quick and obvious.
General view is that kinds of time/fuel efficiency improvements that Free Flight promises are:
(1)
unlikely to be realized;

(2)
not applicable to their operations (east coast, max FL350);

(3)
too costly for them to afford in terms of initial investment in equipment;

(4)
too scary in terms of pilot responsibility for self separation; and

(5)
of a magnitude that is considered within the “noise” of their operation.

Free Flight advantage for this small airline would be:
(1)
reduced delays, both departing and en route; and

(2)
better information, particularly to avoid diversions and replans to stop at unscheduled airports because of insufficient fuel due to bad wind data, excessive vectoring, etc.

Unnecessary diversions and delays are much bigger dollar items than the fuel savings of optimal routes.
Package Carriers

Causes for Replanning
The most common causes for replanning are winds that are worse than forecast, or the crew may call and say they’re burning fuel faster than predicted in the flight plan, possibly due to a mechanical problem. The airplane may develop a problem that requires them to slow down, preventing the fuel burn they expected and putting the airplane over landing weight, so plans have to be made to burn the extra fuel off. ATC may vector them significantly off the route. Or weather at the alternate may go down. If no other nearby alternates are available, it may be safest to divert en route rather than continue to the destination even though it may still be open. Or they may decide to add a leg en route, or overfly a planned stop. If an airplane breaks, an airplane with a light load may stop there. The most prominent reason is weather at the destination or alternate. More major replanning is done for international flights where they don’t get the track or altitude they expected. If a diversion is required, the dispatcher will send the message over ACARS. If the crew is late in the approach, this avoids distracting them at a crucial time. Such a diversion request may be made if, for example, the airplane on approach is going there to cover for a broken airplane and the broken airplane’s been fixed, or another airplane is broken worse in a different location; in either case, the airplane on approach is no longer needed at that location.
　
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