Pillbox is one of the most popular maps on bzflag. It is a capture the flag map with two teams. The tanks are not meant to jump. PillBox even had a Pillbox_League and is now one of the official maps from Leagues United.
The following page is a short tactics guide. It is mainly aimed at public servers where each team has 5-10 player.
Teams should always have at least one tank defending the square containing it's team base. Otherwise it is easy for the opponents to spawn and steal the flag. If your base is undefended, go and defend it. This is especially important right after your team has stolen the enemy flag, because the rest of your team-mates will probably charge the enemy base leaving your base as an easy target for spawners.
If the enemy is not attacking then it is wasteful to defend a base with more than one tank, so if you see another tank defending, you then may leave the base and attack as fast as possible. However if the other defending tank is a newbie or otherwise lacking in skills, then you should encourage them to attack, so that you can stay back and defend. Sometimes it helps to drive very close to your base. This may cause the other defender to attack on their own.
It is better to charge than to camp outside the square that contains the enemy base. Nothing is lost by charging because if one fails then one may re-spawn and attack again.
One problem with camping outside the square with of your opponents base, is that your opponents will keep spawning close to their teammates. In other words the opponents will spawn close to the place where they die, so it's virtually impossible to empty the square from opponents.
In general it is impossible to keep all the tanks of a team away from the map for a long period of time. The best one can do is to force them to spawn in one of the two corners that do not contain any bases. If they spawn in such a corner then they will be too far away from the flags to make much of a difference to the game.
It's good to often try to attack the opponents base along the far edge wall. It takes a little extra time to drive all the way to the edge wall, but once you are there it becomes easier to attack. One benefit is that the enemies may not notice you, so sometimes one can get close to the opponents base before being noticed. Secondly it is sometimes possible to shoot some defenders easily without much opposition due to the fact that they might be pointing in the other direction. (It can also allow team-mates the chance to shoot them as they start rotating towards you.)
It is best to take chances to steal the enemy flag, as one has a good chance that their teammates have a good chance of killing the opponents, then one may start driving directly towards the base even though some defenders are still alive. This way one may be able to steal the enemy flag so early in the game so that the rest of the opponents team has no time to arrive and defend. (Of course one should only do this if one is closer to the enemy flag than any of their team-mates).
Sometimes an enemy will hide behind a box. In this situation it helps to attack together with a teammate, so that you might be able to flank them.
Returning with enemy flag
If you have stolen your opponents flag one should always start out looking at the radar at lowest zoom, this is done to avoid choosing a route that takes one through an area which a situation of 1vs2, 2vs3 or so for the player which is carrying the opponents flag.
Some experienced players are able to drive through the center with an enemy flag, but it is difficult to do and usually leads to one getting stopped by opponents. One problem is that if one loses the enemy flag somewhere around the center of the map, then it usually leads to a stalemate for a good period of time. Meanwhile the opponents have time to pick up your teams flag and score a flag capture.
Instead one should try to take a route that takes one past one of the two "buildings". This makes it simpler for team-mates to defend and easier for them to pick up the opponents flag if one loses it. One should not to change direction too often, as it slows one down and also ones team-mates needs to be able to predict where one is going so that they may be able to help.
Finally one should try to run the opponents when one has it. It is often better to take a chance and move fast than it is to take cover and wait for teammates to come to help one out.
The one exception is that when your base has several opponents around it when one arrives. In this situation one has no chance to get through to ones base without help. And if one dies in the middle of a crowd of opponents then it becomes easy for them to save their flag. If this situation occurs, try to camp close to the edge wall just outside the square which contains your base. That causes the enemies in the square to turn around and attack me to save their flag, and then allows ones teammates to catch up and to have a chance to shoot them from the rear.
Saving your team flag
If an opponent has taken your flag, then one should try to stop him as quickly as possible. Sometimes this may require one to drive away from an opponent that is firing at you. Because one has no time to stop and shoot back. This can be frustrating, but the best way to help ones team is to attempt to save ones flag. Sometimes the enemy flag carrier is defended by a group of teammates. If this occurs one should fire at flag carrier rather than the opponents teammates. The problem if one fires at the opponents teammates the flag carrier is likely to get away and it doesn't help to kill his teammates, but if ones kills the flag carrier then it takes time for their teammates to pick up the your flag.
Sometimes it's best to take the enemy flag even though our own flag has been stolen. Because one may still have a chance to outrace the enemy flag carrier, and capture it before the opponent does. But in some cases one is far behind and never outrace the opponents flag carrier. When this occurs it is best to ignore the enemy flag and try to stop the enemy flag carrier. The problem is that if one stands close to the opponents base then one may be the only tank in ones team that has a chance to stop the enemy flag carrier.