Given that LAS/LAZ is LiDAR point cloud data, there is a GIS tool called las2tin to convert these files to a triangle based mesh called Triangular irregular networks or TIN by the GIS community. Once you have the mesh, Google should be able to help you find a way to convert the TIN to an STL. You will need to scale down the STL after creation, as the TIN will probably be at 100% scale.
More details for the process that I got from Google are available here