Ticket purchased by relative in USA for travel from India

hi greetings

We live in USA and our aunt is travelling from India to USA in a few days. I booked ticket for her from USA using my USA bank issued card. On the ticket issued, there is a mention of 'additional validation may be required'

She will not be carrying the credit card used to book ticket with her. Can you pl clarify if she needs any additional documentation to carry. Should I give a letter to her that I booked ticket from USA along with my contact information. Thanks