Yes to enter Meghalaya by air or by road you need to have a Covid Negative Test report done in last 72hours. You also need to download Meghalaya Tourism's App add names of all ppl travelling along, your itinerary and stay details to obtain an e-invite. Its the RT-PCR test they are looking for not the Rapid Antigen Test. All the details are very clearly given on Meghalaya Tourism's app and website.