VPC Flow Logs can now either log to CloudWatch or to an S3 bucket

Just for your information: you can now choose, wether you want to log the VPC Flow Logs to Cloud Watch Logs or to an S3 Bucket:

https://aws.amazon.com/about-aws/whats-new/2018/08/amazon-vpc-flow-logs-can-now-be-delivered-to-s3/