Plese help with sound

Hello, I'm really a noob when it comes to coding. I am trying to make a script that will play sounds when my avatar if flying. But its not working. To me it looks correct. Can somebody look at this and tell me what I am doing wrong?
Thank you all so much for your kind help in here.

default
{
    state_entry()
    {   
        if(llGetAgentInfo(llGetOwner())&AGENT_FLYING)
        {
            //Flying
            state flying;
        }
        else
        {
            //Not FLying
            state notflying;
        }
    }
}

state flying
{
    state_entry()
    {
                llPlaySound ("UUID", 0.5);
	llSleep (2.5);
	llLoopSound ("UUID"), 0.5);
    }
        
    timer()
    {
        if(!(llGetAgentInfo(llGetOwner())&AGENT_FLYING))
        {
            state notflying;
        }
    }
}

state notflying
{
        state_entry()
    {
        llStopSound ();
    }
    
    timer()
    {
        if(llGetAgentInfo(llGetOwner())&AGENT_FLYING)
        {
            state flying;
        }
    }
}

You've not used llSetTimerEvent. The code in the timer will only check whether someone is flying or not if it's actually active. Put in a call to it in all of the state_entry blocks. I'd think that llSetTimerEvent(1.0) should be perfectly fine, no need to go below that.

Incidentally, I wouldn't bother having three states - just make the default "notflying" and keep "flying", or vice versa. It will only make a difference if you reset the script, and then only for a tiny period of time.

Thank you very much. That got it working great.