Combat with Flying Units

Flying Units are handled poorly in Savage Worlds and Palladium Rifts and, I imagine, in a lot of other games as well. The speed at which they travel makes tabletop gaming nearly impossible. As a result, I've developed these rules for handling fast aerial vehicles and other speedy fliers in combats that also includes slower land-based units.
First, I use hex grid instead of square grid. If you prefer to use square grid, then include diagonal movement for a total of 8 possible directions. All other rules would be the same.
Second, because aerial vehicles move so rapidly, don't bother putting them on the map at all. Rather, have the pilots declare the path they take as they make an attack run. See the following image of a flight path on a hex map for an aerial attack on a ground unit. The flight path shall be a straight line from one edge of the map to the other. It may originate from any side of the map, unless the GM establishes that it shall not.

At the GM's discretion, the flight path may include a single bend, but that would be dependent upon the maneuverability of the vehicle and the piloting skill of the pilot. The flight path upon entering the map must be in line with the target and the bend can occur at any point before or after it would fly over the target hex, so long as there is a line of sight for three consecutive hexes between the flying vehicle and the target hex before the bend occurs.

When the pilot makes the attack run, the pilot must state the altitude of the attack run. The pilot can choose any number from 1 to 5. This is done for two reasons.

• It establishes the line of sight requirements. Every level of cover blocks line of sight for 6 hexes minus the altitude of the attack run. So, for an altitude of 1, each elevation of cover obscures the line of sight for 5 hexes behind it. An altitude of 5 obscures only 1 hex behind it.
• It establishes range. The altitude adds that number of hexes to the range of any attacks from or to the flying vehicle. So anyone firing at the flying vehicle would calculate the distance to a hex on the flight path and then add a number equal to the altitude of the attack run.

Pretty simple.
Additional factors to take into account:

• If anyone wishes to attack the flying unit, there shall be a minimum number of hexes the flyer must be visible along its path in order for any units to attack it. So just like there is a requirement for the pilot to have the target in view for three consecutive hexes prior to attacking, so any defenders must have the flying unit in view for three hexes prior to attacking it. This can be modified at the GM's discretion based upon any optical targeting systems the firer may possess, or lack thereof.
• A ground-based unit with a lower initiative for that round can not fire at a flying vehicle during its attack run. In game terms, they just were caught looking the wrong way when the flying vehicle zipped past. Ground-based units with higher initiative can only fire at the flying vehicle during its attack run if they hold their turn to do so. In this case, the person attacking the flying unit can state in which hex the pilot's vehicle is attacked. All results of the attack upon the flying vehicle are resolved in that hex prior to the pilot resuming the rest of the flight path.

by Tulcor

In the above illustration, the pilot chose the flight path depicted to attack the target hex. Because of Tree #1 in the 7th hex of the flight path, the pilot must choose an altitude of at least 4. This is because the pilot must have the target in sight for three consecutive hexes prior to attacking it. The tree would obstruct the target hex , preventing the pilot from seeing it for three consecutive hexes at altitudes of 3 or less. At an altitude of 4, two hexes behind the tree are obstructed (6 minus 4), allowing the pilot to see hexes 10, 11 and 12. That is 3 hexes, so it qualifies as enough to conduct the attack. At an altitude of 3, hexes 8, 9 and 10 are obstructed. This means that the pilot was only able to line up the target for 2 hexes and would be unable to conduct the attack against that target hex from that altitude.

The pilot makes the attack run at altitude 4, meaning that every level of obstruction creates a two-hex blind zone. (these trees are level 1 obstructions) Since the pilot can see the target as soon as it enters the map (because there are no higher obstructions than Tree #1), the pilot chooses to conduct his attack when his vehicle reaches the third hex of his flight path. Three units (A, B and C) have a higher initiative than the pilot and have chosen to hold their action in the hope of shooting it down. Unit A can not see the pilot's vehicle until it reaches the 9th hex in its flight path because of Tree #2. Thus it can fire at the pilot's vehicle when it is in hex #11. Unfortunately for the defender, that attack will occur after the flying unit's attack on the target hex. Unit B is three hexes from Tree #3 and so its view is not obstructed at all. Therefore Unit B can choose to attack the pilot's vehicle at any hex from 3 onward. Unit C can only see the pilot's vehicle up to hex 7, after which tree #3 obstructs its vision of the flying unit. Unit C chooses to attack when the pilot's vehicle is in hex 3. It cannot attack the flying unit earlier because it needs to aim at the flyer for three hexes prior to firing. That is the same hex in which the pilot makes its attack on the target hex, so the attacks are considered simultaneous attacks. The range from C to the flying vehicle at altitude 4 in hex 3 is 16 hexes (12 to hex three plus 4 altitude = 16).
When determining who attacks whom and when, it is best to count along the hexes of the flight path in order. This allows both the pilot and any defending players to state what occurs when the pilot's vehicle is in that hex.

Combat between two flying vehicles should be handled off the map, narratively. I recommend using the chase rules for dogfights since they can be adapted with little effort.
Additional Rules for non-fixed weapons:

• unguided rockets and mounted weapons like wing or nose-mounted guns are restricted to firing along only the single line of hexes directly ahead of the flying vehicle at the time they are fired
• hand-held weapons and weapons on the head (including breath weapons) may also be fired at one hex on either side of the single line of hexes directly ahead of the flying unit PER ALTITUDE. So a unit flying at altitude 3 would be able to use a handheld weapon on the single line of hexes directly ahead of the flying unit and up to three hexes on either side of that single line. Note, that each additional hex should be counted for range purposes.
• weapons of passengers, turret mounted and side-mounted weapons are not restricted except as dictated by the design of the aerial unit. For instance, hull mounted weapons on one side can not fire at targets to the opposite side. Likewise, turreted weapons and weapons held by passengers with a rate of fire greater than 1 can fire to the front OR the rear (if applicable) and one side but not both sides during a single attack run.

Additional Rules for dedicated anti-aircraft defenses

• weapons systems linked with dedicated anti-aircraft fire control systems, such as those in fortifications or purpose-built anti-aircraft units may ignore the initiative restrictions of firing at fast flyers. Such weapon systems may attack the fast flyer on their turn regardless of initiative. When an attack is made against a fast flyer, it shall be considered long range if the fast flyer is not on the map.
• Dedicated anti-aircraft weapon systems with greater initiative than a fast flyer may hold their turn and declare their attack when the fast flyer is at medium or short range for that weapon, even if the fast flyer is still off the map.
• Dedicated anti-aircraft weapon systems may only take advantage of these additional rules if they have an unobstructed field of fire. In order to enforce this, the pilot of the fast flyer may be required to state the altitude of an attack run before his or her turn occurs in order to determine whether the anti-aircraft system has an unobstructed view. The pilot does not have to declare the intended target of the attack run at this time, just the altitude. Note: GM discretion is advised here. A single tree three hexes away from a weapon may block it for an altitude 3 attack run, but if the pilot attacks from a completely different direction than the tree, the defending unit may cry foul. Therefore, it is also advised that the pilot declares which map edge they will approach from.
• The GM may put a fog of war in place such that the pilot should only be aware of the location of ground-based units where they were last seen, if seen at all.
• It is possible that the sensors of a fire control system may be elevated above any obstructions. If such sensors are linked with guided weapons that can go around obstructions or weapons that can shoot through any obstructions in their way without losing efficacy, then the anti-aircraft weapon system may attack the fast flyer regardless of the presence of obstructions.