Folder structure of both frameworks are different then each other.
Codeigniter is more reliable then laravel as risk of issues and bugs are less in codeigniter.
As compare to Codeigniter Laravel framework reduce the critical task of developing a site in less time and also, increases the website efficiency. It makes use of many packageas for Laravel PHP development with fast speed, quick installation, extension ability etc.
Codeigniter not supports HTTPs protocols, Laravel Supports the HTTPs protocols and increases the website security level.
Laravel support Explicit Routing and Codeigniter supports both Explicit and Implicit Routing.
Laravel provides RESTful APIs support inbuilt but in codeigniter need to write extra code to integrate the RESTful APIs.
Laravel Uses Eloquent ORM (Object Relational Mapping) for object relations, Codeigniter uses Active records instead for the relationship management through models.
Laravel is more secure and its provide strong authorization and authenitication then codeigniter.
Codeigniter have its own template engine this is based on templating language and its easy to understand, Laravel used Blade template engine to optimize the website performance.