 Production of Thunderbirds ended in August 1966 with the completion of the sixth episode of Series Two . In February that year , it had been reported that Grade had been unable to sell the series in the United States due to disagreements over timeslots . In July , he cancelled Thunderbirds after failing in his second attempt to secure an American buyer . The three major US networks of the time – NBC , CBS and ABC – had all bid for the series , with Grade repeatedly increasing the price . When NBC withdrew its offer , the other two immediately followed . 
 Production of Thunderbirds ended in August 1966 with the completion of the sixth episode of Series Two . In February that year , it <a href='been_done' title='1'><mark>had</mark></a> been reported that Grade had been unable to sell the series in the United States due to disagreements over timeslots . In July , he <a href='uninflect' title='2'><mark>cancelled</mark></a> Thunderbirds after failing in his second attempt to secure an American buyer . The three major US networks of the time – NBC , CBS and ABC – had all bid for the series , with Grade repeatedly increasing the price . When NBC withdrew its offer , the other two immediately followed . 
Production of Thunderbirds ended in August 1966 w da completion of the sixth episode of Series Two . In February that year , it done been reported that Grade had been unable to sell the series in tdaUnited States due to disagreements ova timeslots . In July , he canceled Thunderbirds after failing in his second attempt to secure an American buyer . The three major US networks of the time – NBC , CBS and ABC – had alll bid for thdaeries , witwade repeatedly increasing the price . When NBC withdrew its offer , the other 2 immediately followed .