See pellets in flight?

I can usually see them unless it's super close range. It's easiest for me to see pellets in flight for shots at an upward angle. 

It's usially no problem. The only problem is if a squirrel sees one and moves out the way, which has happened a few times at longer range. 

I also find It helpful for quick aiming, especially in the wind. If I see where shot one goes, correcting for shot 2 is easy. 
 
Alan, I have sometimes shot an air rifle into a group of very dark Conifers (at approx 60 metres away & a safe back stop) just to see the pellet's flight, or most of it. It can be helpful when issues occur. It's better to do that in late afternoon Winter Sun, with the Sun behind you.

Standard 'new' pellets seem to show up alright.