Good Afternoon, First of all - thank you so much to Red Nose for the wonderful resources you have available. I'm expecting my first baby any day now, and I have found your website to be incredibly well-resourced and full of helpful advice. Thank you again. We have just recently had a car seat installed and I have made sure that it meets the appropriate Australian safety standards, and is safe for a newborn. I'm just surprised by the angle of the seat, considering that the safest sleeping practice for a baby is to have them completely flat on their back. Is it normal for a newborn to be positioned at (what seems like) such a severe angle in a car? I know that babies often fall asleep when being driven around, and I can't help but feel concerned that their airways may be more easily blocked in this position. Any advice to make this as safe as possible would be much appreciated. Thank you!

Baby car seats are designed as a safety device not as a safe sleeping product.
It is important that you have purchased a device that meets & is installed as a per mandatory safety & manufacturer’s instructions, which is also a legal requirement.
Yes, of course baby’s will go to sleep in their car seat, but baby should not be left for long periods sleeping in a car seat.
Red Nose has no specific recommendations for time frames when travelling with baby in a car safety device but has the following information.

Once the car journey is over it is very important that you remove baby from the car seat or capsule, even if this means waking baby, because it is not safe for baby to spend long periods in car seats, capsules or infant seats.

Research has shown that:

babies left in a sitting position for a long period of time may be placed at increased risk for sudden infant death.
car or baby seats may cause baby’s neck to flex forward which may block baby’s airway not allowing airflow
falls from car seats used outside of the car as infant carriers are common, often involve children unbuckled in their car seats and represent a significant source of head injury for baby. Never leave baby in carriers on shopping carts, counters, or other high locations
https://rednose.org.au/article/are-there-recommendations-for-car-seat-or-baby-seat-use

Most safety organizations would follow travelling advice for all when driving long distances - take a break every 2 hours (or less)....... so, this would be applicable for baby also.
When you stop for a break, get baby out of car seat/capsule even if baby is sleeping.

If you are going shopping with baby, do not carry baby in a capsule, instead use a pram when baby is lying flat.