Marcel Bloch was a true aviation pioneer. His firm led French aviation before WW2 and he restored that leadership afterward. His aircraft were world class, even though his resources were never more than a fraction of those available to his competitors.
Serge was much more multi faceted; apart from his aviation interests, he was a very successful real estate investor and also a leader in digital data systems through Dassault Systemes, as well as a parliamentary representative. Serge was very conscious of his responsibilities to his firm and his work force. so he was always financially conservative. The continuing existence of Dassault is a tribute to his obstinate determination to keep his firm independent.