To Altai And Back

For a summary of information on the native Altaians, see here.

OK. I have reconstructed Flandry's itinerary. For the investigation of Altai:

Intelligence shipped him to Betelgeuse, where the Terran Embassy gave him his orders with a dossier and an expense account;
he engaged passage to Altai on a Betelgeusean trading ship.

To return to Terra:

he engaged passage on a Betelgeusean tramp ship as the quickest way to reach the Imperial port at Spica VI, from where he would return home on a luxury liner, the Empress Maia;
however, the tramp stopped on Orma, where a Betelgeusean trader informed him of another isolated human colony, Unan Besar, and he rented a space flitter to go and investigate that planet;
presumably, having liberated Unan Besar, he returned to Orma, thence to Spica VI and Terra, although we next see him, some time later, on Varrak in the Taurian Sector - if you accept my revision of the Chronology in recent posts.