Moving object in winform not smoothly

See more:

C#

WinForms

graphics

I have an object that can move in any direction(user define) but as you can see, it doesn't move smoothly.
how can I improve this movement.
here is a video of this object movement.

bandicam 2022-06-12 10-43-26-451.mp4 - Google Drive[^]

 private void timer2_Tick_1(object sender, EventArgs e)
       {
           float xpos,yapos,yspos,dif;
           double atheta;
           if (aireplane1.Top >= brec.Top + 10)
           if (startmove && !airisdragging)
           {

                   Size aireplane_size =aireplane1.Size;
                   if (keynum>0 && keynum<180) {
                   atheta =  Math.Atan2(aireplane1.Location.Y , aireplane1.Location.X);
                  atheta = atheta *180 / Math.PI;
yspos = -(float)Math.Tan(Math.PI/2- keynum * (Math.PI / 180)) * aireplane1.Location.X;
                   dif = yspos-aireplane1.Location.Y;


 xpos =( aireplane1.Location.X)+2;
                   yspos = -(float)Math.Tan(Math.PI / 2-keynum * (Math.PI / 180)) * xpos;
                   yapos = yspos - dif;
                   aireplane1.SetBounds((int)xpos,(int)(yapos),aireplane_size.Width,aireplane_size.Height);
                   }
                   else if (keynum >180 && keynum < 360)
                   {
                       atheta = Math.Atan2(aireplane1.Location.Y, aireplane1.Location.X);
                       atheta = atheta * 180 / Math.PI;
                       yspos = -(float)Math.Tan(Math.PI / 2 - keynum * (Math.PI / 180)) * aireplane1.Location.X;
                       dif = yspos - aireplane1.Location.Y;


                       xpos = (aireplane1.Location.X) - 2;
                       yspos = -(float)Math.Tan(Math.PI / 2 - keynum * (Math.PI / 180)) * xpos;
                       yapos = yspos - dif;
                       aireplane1.SetBounds((int)xpos, (int)(yapos), aireplane_size.Width, aireplane_size.Height);


                   }
               }

       }

keeynum is user angle input.

by changing time intervals the movement become smoother but still the background of the path of airplane change when it across it, how can I fix this?

bandicam 2022-06-13 17-18-00-689.mp4 - Google Drive[^]

What I have tried:

I didn't do anything more than this