I don't think you saw any hacks, only some glitches. Some of them were caused by a problematic anet2.dll in BZ 1998 v1.3. Download the
stock anet2.dll and place it in your main BZ folder. When you say "above the map" I'm assuming you got the notorious wrong-map-glitch, so you were on a different map than your opponent, which is quite a weird sight, causing them to be "above the map" while on their screen, you are "under the map". That was caused by wrong DLL. If you were to rejoin the game, you'd then be on the correct map. If you were host, your flying or underground opponents would need to rejoin the game.
Hackers are not allowed on battlezone1.net server, the server is heavily moderated. I suggest you give BZ another chance, and if you DO happen to see what you think is a hack, don't quit BZ, make a video of the alleged hacker and get his IP. From the video we can tell if it's a hack or just a glitch. Believe me, I've been frequenting the battlezone1.net server ever since it got set up, and I have only seen hacking a couple of times, and the offender got banned for a week. After that, I have seen 0 hacks, but a few glitches.
Battlezone was really bad on the old server before battlezone1.net, anybody could hack and not get consequences.

Was a complete mess, the administrator didn't care. Things are much different now.
Edit by Mr. Spock: Different map glitch topic.