Display attributes - You can display these attributes of the main info object in the query but cannot drill down beyond these attributes and apply some formula's.
Navigational attributes - You can display these attributes in the query as well as apply drill down beyond these attributes and apply formula's and do some calculation.
For query performance, it is recommendable to keep attributes of main info object as display until user specifically request for it. System default for attributes is display until you change it to navigational.
Display and Navigational type of attributes differ by their functionality only.
There will be no difference while they form as objects in the Universe .
But in the reporting application ( Web Intelligence Documents) , we can place use display type of attributes in result objects section but not in Query filters section. Where as navigational attributes can be used to restrict the result set by placing them in Query filter section. Its same like BW we can not perform drill functionality on display type of attributes and we can on navigational attributes.
The difference of display attributes and navigational attributes w.r.t SAP Business Objects.
Display Attribute: Display attributes are available as sub-ordinates of the characteristic.
Navigational Attributes: Navigational Attributes are being treated identical to a characteristic.