At close to 1,900 km, Goa from Delhi is almost exclusively a flying trip - roughly 2.5 hours direct - since driving would eat up multiple days each way. An overnight-plus train option exists (around 24-30 hours) and remains popular with budget travellers who don't mind the extra time.
Because of the distance, Delhi-origin Goa packages tend to run a full 4-5 days rather than the shorter 3-day versions common from closer cities like Mumbai, to justify the longer journey with a fuller beach holiday.