#define FILTERSCRIPT

#include <a_samp>

new timer[MAX_PLAYERS];
new savetp[MAX_PLAYERS];
new dives[MAX_PLAYERS];

/*
native SetPlayerPosition(pid,Float:X,Float:Y,Float:Z);
*/

#if defined FILTERSCRIPT

public OnFilterScriptInit()
{
	print(" Antifly");
	return 1;
}
#else

main()
{
}

#endif
public OnPlayerConnect(playerid)
{
	dives[playerid] = 0;
	return 1;
}
public OnPlayerUpdate(playerid)
{
    if(GetPlayerAnimationIndex(playerid))
	{
	new animlib[32];
	new animname[32];
	GetAnimationName(GetPlayerAnimationIndex(playerid),animlib,32,animname,32);
	if(strcmp(animlib, "SWIM", true) == 0)
	{
	new Float:X,Float:Y,Float:Z;
	GetPlayerPos(playerid,X,Y,Z);
	if(Z >= 8.45)
	{
	if(!IsPlayerInRangeOfPoint(playerid,37.85,1964.0404,-1199.6774,17.4400))
	{
	dives[playerid] = 1;
	}
	}
	}
	GetAnimationName(GetPlayerAnimationIndex(playerid),animlib,32,animname,32);
	if(strcmp(animname, "FALL_FALL", true) == 0)
	{
	new Float:X,Float:Y,Float:Z;
	GetPlayerPos(playerid,X,Y,Z);
	SetPVarFloat(playerid,"Float",Z);
	SetTimer("Checkhim",1200,false);
	}
	}
    new index = GetPlayerAnimationIndex(playerid);
	if(index >= 958 && index <= 962)
    {
    if(GetPlayerWeapon(playerid) != 46)
    {
	dives[playerid] = 1;
    }
    }
    if(dives[playerid] == 1)
	{
	SendClientMessage(playerid,0xC30000FF,"You are banned Reason: Flyhack");
	Ban(playerid);
    for(new i = 0; i < MAX_PLAYERS; i++)
    {
    if(IsPlayerAdmin(i))
    {
    new string[100];
    new name[100];
    format(string,sizeof(string),"%s has been banned Reason: Flyhack",GetPlayerName(playerid,name,sizeof(name)));
    SendClientMessage(i,0xC30000FF,string);
    }
    }
	}
	return 1;
}
stock SetPlayerPosition(pid,Float:X,Float:Y,Float:Z)
{
	savetp[pid] = 1;
	SetPlayerPos(pid,X,Y,Z);
	KillTimer(timer[pid]);
	timer[pid] = SetTimer("remtp",15000,false);
}
forward remtp(playerid);
public remtp(playerid)
{
	savetp[playerid] = 0;
	return 1;
}
forward Checkhim(playerid);
public Checkhim(playerid)
{
	new Float:X,Float:Y,Float:Z;
	GetPlayerPos(playerid,X,Y,Z);
	if(Z > GetPVarFloat(playerid,"Float"))
	{
	if(savetp[playerid] != 1)
	{
	dives[playerid] = 1;
	}
	}
	return 1;
}

SendClientMessage(playerid,0xC30000FF,"You are banned Reason: Flyhack");
    Ban(playerid);

Source: The fucking script itself, took me 4.753 seconds to find this.