Can AWS default VPC be deleted? I checked AWS documentations and it seems the following two are against each other. So I opened a ticket with AWS, and here is their answer:

Technically yes, you can delete default VPC's and create a non-default VPC. 
Some services such as CloudFormer to create CloudFormation templates do 
searches for default VPC during creation if non-default VPC parameter is 
not defined. Deleting the Default VPC will not cause any underlying issue 
or restrict usage of any AWS service.


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