Just curious as to why Delhi would be operated as a seasonal destination?
Winter is the best time to visit India - too hot/humid in the Monsoon. Also it is when most decide the auspicious dates for arrange are so VFR traffic.
VS did have an arrangment with Jet Airways. It would be difficult to know who to share with now- other than Air India almost everything else is low cost and largely point to point. But cheap - so ethically Indian folks (and 22/04) would probably use SpiceJet or Indigo given the need to reclaim baggage anyway.