Chances are baby will get hungry soon after you both go out. Even if you feed, burp, and change baby's nappy right before you leave, be prepared for baby to want to eat again before you get to your destination. Wear clothes that make it easy to breastfeed and bring along a change of breast pads. If you're concerned about having to breastfeed in an unfamiliar place or are going someplace where you'd prefer to be extra-discreet, add a blanket or shawl to the gear for added privacy.
For a formula-fed baby, it's best to take along powdered formula that's been premeasured into a bottle. It's easily mixed with water, wherever you are. Bring along bottled water if you're unsure of the water supply (or on an airplane, ask your flight attendant for it, so you don't have to use the tap). Or take along ready-to-drink formula. A bottle needs to be warmed only to room temperature; try putting it in a bowl of hot water. But some babies actually prefer a cool drink! (Remember: discard any formula left over in the bottle.)
Our parenting advice is given as suggestions only. We recommend you also consult your healthcare provider, and urge you to contact them immediately if your question is urgent or about a medical condition.