Problem: The Fly tool is missing from the Tools toolbar in ArcScene
The Fly tool, which provides an important way of navigating about a scene, should be available by default on the Tools toolbar.
This tool was added to the product late in the release cycle.
Solution or Workaround
The tool can be found under the Viewer category on the Commands tab of the Customize dialog box.
You can add it to a toolbar (typically the 'Tools' toolbar containing the other navigation tools) by dragging and dropping from the Customize dialog to the toolbar.