Fetch all data from two different collection using single query

Hello… can you help me with a query that can fetch all data from two different collections in a single query.

consider example:
there are two models carBookings and bikeBookings. which contain booking details. both have a common field customerId. I want bookings from carBookings and bikeBookings which satisfy condition same customerId in a single query.
waiting for your help.

Take a look at $unionWith.