What your dog sniffs - air or ground - shouldn't be so important to you, unless the object of search is hidden in the canopy. He shouldn't pay attention to you during the search and be totally self-motivated. It is you who should be fast enough to follow him, though, it all depends how fast your dog moves. For instance, my dog ia moving slowly and working the gound surface thoroughly while performing a grid search, and I don't have any problem following her. But, my instructor's dogs are very fast, she is using two of them at once, they dissapear out of sight only they were cued to search, but they don't run away too far and always come back asking their handler to follow them. You have to train your dog doing that.
When your dog finds the object he must take you to it, i.e. return to you, jump on you or indicate some other way, and with the command "Show me" take you to the source. This technique is called a "refind". Don't use a large square to start training. Hide the container with the scent at some tree, mark the tree with a red thread (so you know exactly where it is hidden), come to the area the next day and ask him to search a short distance before you approach that tree. When you saw your dog indicating clearly at the object , stay where you are and reward him with the clicker. Then call him to yourself, fondle him, ask "Show me" in exciting intonation and cue to search again - this time follow him dirctly to the hidden object. Reward when you come to the object yourself. Repetition after repetition, finally your dog would learn this last step of search.
The troubleshooting here mainly with the handler, not with the dog, the handler has to learn to believe the dog when he alerts and react properly, because you never know where the object is hidden during a blind search.